That is the nature of our game, no electronics last forever. A few years ago the owner of the company that created the EVO publicly claimed bankruptcy/closing and then a few months later opened up under another banner. *That* line of accordions was kind of promised around 2019-2020, but COVID put a plug in that one... and today, coming up to3 years later, there are no new developments other than the posts/videos made.
Petosa became the only place in North America to sell and service the EVO. I don't know how they can service them unless they bought out some spares or are cannibalizing other accordions for parts.
As far as Ketron, at least they have been around a long time and seem dependable. I also own an X4 and it works 100% to this day. Not bad for being "alive" for 20+ years. Our choices in the world of digital accordions is really limited and it's too bad that there is nothing out there that can do what the 8X does... it many be tiny, but I feel that there is a market out there for it.
Concerning the SD-90, there was an earlier issue with it on the 8X, but I believe they addressed it. As for how it would run on the EVO, it is so close in that respect to the FR-8X that talking to those people the experience would have to be pretty much identical, and I would have to say in terms of effectiveness, the same as the X4, just with all the added bells and whistles that it has. Basically... MIDI is MIDI.