I have to admit that I didn't see a recurring subsription pricing model coming at all. I'm not opposed to the model in general, but I just can't imagine paying $50–60/year for... an email client... I'm scratching my head if there's ever been a (personal) email client (not service) billed similarly. Very weird decision by the founder... sorry, but I'm not buying.
It also feels super shitty to launch 1.0 out of the blue AND then expire the public beta builds that we have been using for 3 years with 4 days notice...
I hate to say it, but this feels like a totally botched overnight transition from longtime free beta to paid app to me. There wasn't even a notice given to existing users that 1.0 was coming (now or later). From the outside, it looks like they hired multiple engineers too fast, maybe they tried to raise VC and it failed, and this is an effort to pay the bills.
I think this pricing is out-of-touch with their userbase and making this drastic move randomly will cause them to lose 95%+ of their users. I would have given them a $30–50 one-time purchase for sure (i.e., something like Sublime's license model).