Companies do this all the time especially when there's an acquisition or change in management. In some cases they may technically still support it but with ever growing bugs, security issues and so on.
You’re conflating “free software” with “community support”. It’s possible to run free software with a paid support contract backed by a corporation - thats what RHEL offers, and Ubuntu with their Ubuntu Advantage program.
CentOS offered free software, but with unpaid community support, which isn’t guaranteed at all as there’s no contract.
This is an unpopular opinion but this is why I prefer Ubuntu over Debian - there’s a corporation on the other end that’s being paid to update software, and if you choose, you can always upgrade to paid support that is backed by a legally binding contract.
If you're using open source software and not paying anyone, sometimes shit happens and you will be surprised or disappointed and have no recourse. Even if everyone starts off with the best of intentions.
We could debate forever about whether fault lies with projects overpromising, or users having unrealistic expectations, or whatever else, but I don't think that changes the situation.
If you have are paying someone for the software/support, shit still happens, but you have a relationship and ways to get recourse.
Sadly, the danger of running on free software.
Even more sadly, this puts a bad taste in peoples mouths, making them hesitant to start new projects on free software.