I suppose that their marketing department has decided that Linux
Developers/Users don't represent a big enough share of the market to
justify committing more resources to the platform.
However JACK also runs on the other two main platforms so what is their
rational behind completely ignoring it altogether while committing
resources to creating a competing API?
Keep in mind that they have explicitly stated that Ableton Live will NEVER
run on Linux. It seems a bit hypocritical to me that highly regarded
people from this community are proposing to add support for the new
protocol and at the same time questioning why there is (still) antagonism
towards Ableton.
Other proprietary companies have no problems releasing their software to
run on Linux.