Most of these platforms make no money but have taken huge amounts of VC funding which they have burned through. For the VCs to unload it and cash out they need to show the product can be monetised and them try and shift it before the users leave the platform. Idiot users want all the features of a product developed by lots of talented full time paid staff but don't want to pay for it themselves so they leap from startup to startup then complain when the inevitable happens while dismissing open source alternatives as inadequate for their needs. Why should we care? I don't.
While I don’t disagree with the sentiment, the Discord Nitro subscription has been around for a long while. From what I’ve seen using the platform it seems relatively popular. I’d guess adding ads to the free tier is as much about enticing people onto the subscription (which presumably won’t have ads).
I've been using Discord almost since launch, and in that time, not a single feature did I find as an important addition to the program. It is now much more bloated with unnecessary stuff, stuff for which they paid those talented devs you mention.
I would have been perfectly content with a one-time payment to use it and it would have worked perfectly well for them with that model if they didn't get greedy and want to stuff it with random junk to justify a subscription.
I don't mind paying as long as it's not a subscription scam for no reason at all.