I agree that it is not a small development effort to make a native client to any specific flavor of Linux, and there would be prioritizing decisions that would have to be made in that regard. However, given Evernote's decision to drastically raise pricing for premium members, I am looking for significant investments and development in the core Evernote software. More specifically, I want them to address longstanding issues with the notes editor, pursue stronger encryption/privacy integrations, and create a native client that runs on Linux.
No one cares about things like work chat, and I don't care for being able to link/embed Google documents within notes (two recent features they have implemented). I also don't care what they neuter/remove from the "free tier" of Evernote, because nothing in this world is really free, and I am not against paying for the service.
For me personally, I pay for Evernote Premium, because I do not want my data to be mined within any of the "Big 3" ecosystems (MS, Google, Apple). I don't want to use OneNote, because all of it's best integrations are with the MS Office Suite and MS' preferred web browsers (IE/Edge), which I do not particularly care for. I don't use Apple Notes, because I do not want to be tied to the Mac ecosystem. And I don't use Google Keep, because I simply don't want my data to be mined for Google's needs/profit (not to mention their penchant for discontinuing products).
I use (and happily pay for) Evernote to stay more or less independent of those ecosystems, and I am sure many Linux users who user also utilize Evernote do so for many of the same reasons (even though they only have access to the feature-crippled web app or various third party implementations). I am not against paying for a solid product/service, but with this price change, I am looking for a significant change in priority/vision from Evernote:
cross-platform support should become a major priority including some flavor(s) of Linux,
more privacy-centric features should be integrated into the core product/service
Evernote should remain as independent as possible from the Big 3 I mentioned previously
Given the dramatic pricing increase to my premium subscription, anything less and I am gone from Evernote when I am up for renewal. The current pricing scheme/tiers and feature set are ridiculous when you try to compare it with the value you would get as a consumer out of a modestly more expensive Office 365 subscription.