As someone who has done the technical work of converting a product with a free-tier to a paid product, I mostly agree. I think the problem mostly stems from the transition being inherently painful to a lot of users - it’s not really reasonable IMO for them to expect hosted software to be free forever but it’s definitely frustrating for them to transition off of it if they can’t or won’t pay for some reason.
In my particular case there were a few pain points where I couldn’t help but sympathize with the complainers. For starters, they’re still subject to all the problems stemming from vendor lock-in, so migrating away may require not just a lift and shift but a partial or total rewrite. Another common problem is that they wrote some software for eg a for-fun website or side project a long time ago and don’t check up on it often - they may not even use or have access to the email and other contact info you have at your disposal to tell them that their stuff will break if they don’t pay by a certain date. So a lot of people don’t know about the change until their stuff breaks or they check in one some old project and find it broken or gone.
This was less of a problem for me than it probably is for Replit, but students are particularly impacted because they usually have little money relative to their investment or interest in the thing. Students under 18 without any credit or debit card may not even have any way to pay at all. And also they are still figuring out how things work so they don’t necessarily understand without being told that eg free tiers are primarily meant make it easy for people to try the software before paying for it (the company doesn’t want you to use it forever without paying), subject to a lot of annoying things like abuse, and just generally require a decent amount of operational maintenance to keep running. And of course they haven’t had corporate communication styles beaten into their brains so they’re pretty rude about expressing their discontent.
Basically, I think it’s wrong to feel entitled to receiving a free thing that obviously costs someone money to provide for forever, and that you should just pay for it if it adds value and is reasonably priced. But it’s also inherently frustrating to be on the receiving end of these changes, so grumbling and discontent are only natural.