Hey Andrew!
I was on a trip when I saw your post and bookmarked it, so that I can respond to it later. Hence, a delayed response.
I would like to discuss a couple of things here: the illusion of a music release and distribution platforms.
The illusion of a music release
If you look through the stats, before the Internet and self-publishing, there was a very limited amount of music releases per year. Here's a stat: in 1970, 4,000 albums and 5,700 singles were released in the US. Today more tracks are uploaded to SoundCloud in an hour. Even if we imagine that the numbers in the 90s or even current official music numbers are much higher, self publishing will outpace these releases within hours or days.
This is not simply a qualitative difference, it introduces a qualitative difference as well. And not even in a sense that the self-published music is bad - after all, a lot of officially released music could be bad too. It's just that in order to self-publish, the only person you need to convince is yourself. "I think it's done" is the real standard today. "I think it's interesting and important enough to be shared with the world" is the name of the game.
But if you look at the official releases, they don't work that way. Even if you try to publish with a small digital label, your music should go through someone else, you might be asked to mix it better, it might be mastered, you might even need to go through some bureaucratic process of signing a contract or at least a quick written negotiation of what happens then.
This means that when someone in the XX century said they'd released an album and when I say it, a self-publishing artist of the 21st century, this means very different things. I can tell my friends - "I just released an album". And it will sound as important as it did in the past. But it's really not the same thing. I just uploaded some sound files to a website and then hit "Publish".
Again, this is not to take down the quality of self-publishing works, or the fantastic opportunities of self-publishing that we are all enjoying today. It's just that when we are talking about music distribution, we have to make sure that we are cognisant of the fact that most of us are self-publishing artists, who have been vetted or supported by no one and who are essentially alone in their quest to publish.
Distribution platforms
What we really want, as artists, is an audience.
An idea behind many of the distribution platforms is as outdated as the idea of a music release. In the past, there was only a limited amount of distribution channels. Therefore, publishing an album meant not only a veneer of being vetted and therefore being considered worthy by someone who knows their stuff, but also exposure to a public that essentially had very little options. Definitely, much less options than there are today.
Therefore, the idea was that all we have to do is expose your music to the public - and then it either works out or it doesn't. If it works, we pick you up and for your next release we can provide some additional marketing, radio play, etc. This can also be done if we simply believe in you from the get go.
So, label services translated into
1. actual physical distribution
2. marketing
Today the situation has changed: the utility of physical distribution per se is low to non-existent. But the utility of marketing is as relevant as ever.
And this is a key point: modern distribution platforms promise success by focusing on distribution, which is something they can realistically provide, but which is trivial in the current technological landscape. But what really gives you a chance at becoming successful is marketing, but platforms are usually not promising this and are not equipped to provide it.
Some platforms will have mechanisms such as recommendations which might expose your content to listeners, but even there you usually have got to have a certain amount of plays/followers to be picked up by the algorithm.
But, most importantly, due to the sheer amount of self-publishing artists, your name is now just one among a sea of other names. And this sea of unknown artists is competing with some of the masters of the genre, because the self-publishing space is global, and even established artists routinely use it.
Future of marketing
And so, I think it is more meaningful to instead ask - what is the future of music marketing? And has digital technology made the gap between known and unknown artists actually smaller?
It's not an easy question to answer, but I think some things could be summarized.
1. The potential gap between known and unknown artists became larger, but so did the amount of concentric circles of sub-genres. This means that there are now more artists who are at least somewhat successful and known, but within each concentric circle of a sub-genre or a community becoming successful is even harder than ever due to a rise in competition.
2. Marketing will never become a commodity due to time being a scarce resource: you will always be competing for attention. No platform can ever credibly promise marketing as a service. All platforms that try to sell marketing as a commodity devalue it. A service like Distrokid is valuable, but now simply being on Spotify doesn't mean much: everyone is on Spotify.
3. Therefore, the choice of a platform for distribution is not that important. Not to your success or profit, anyway.
Established platform vs own website
The reason why I would never opt for my own website as a distribution platform is that audiences are used to performance. For instance, Andrew, I tried streaming tracks from your site, and it was painfully slow. It's not your fault. It's simply that modern platforms are spending millions of dollars to make their experience fast and responsive. I work at SoundCloud. A team of 5 people worked on the audio player for several years to make it as fast and responsive as it is right now.
This is especially important if you are an amateur and not known. You don't have enough credibility, and someone might click on your track, it's not loading - and they leave, probably forever.
So, just from a utilitarian point of view, we are forced onto an established platform. But, it doesn't matter too much which one you chose. Or, rather, what might matter here are personal preferences and the minutiae of how you want to engage with your audience. Bandcamp, iTunes and SoundCloud are all very different ways to market and consume music. But, from the point of view of making a living - they are very similar. Differences are contextual and might be important for a given artist, but this is not universal and, on a larger scale, not that important.
I can talk about this forever. I'll stop here. Tell me if any of this makes sense, maybe this is enough to start a conversation.