We have stats. Less than 1% of our player base uses a version older than Windows 10. We can't keep supporting it, and we won't for a small amount of stubborn people. If your PC can run Windows 7, it can also run Windows 10. Alternatively, Linux which we aim to support better in 1.7. You are running an operating system that is insecure, open to viruses, and disallows us from making important changes to improve MTA.
Tens of people, maybe hundreds on a really busy day. Others included in your "millions" don't play MTA, and many of those numbers are taken up by embedded systems with no opinions.
MTA 1.6 had issues. We acknowledged this multiple times. With MTA 1.7 we have worked hard to resolve many of those issue, a commitment that continues. Many of those issues came from having to adapt to more heavy servers (using more heavy assets) and having to further protections against cheaters. MTA is old, with a very old codebase, on top of an old game. It adds unique challenges. We continue to have a large player base that will happily move over to 1.7 once released.
Don't make claims without having the stats to back it up. Don't make claims without a proper understanding of software development, and the efforts that go into a project like this.
Windows 7 support by Microsoft ended over 6 years ago. Similarly we had supported Windows XP for many years after Microsoft did. We don't have a history of ending our support that quickly, and we only do if we have no other choice. Windows 10 will see support for the foreseeable future.
That said, if you have issues with the game, or the default resources. Report them on our GitHub. You can also contribute to those fixes yourself (as we are open source).
Already acknowledged and being fixed for MTA 1.7.
Can't compare us with first-party games. We are a mod for a very old, poorly optimized game. The challenges for these are very different as we don't have access to the game's source code. Servers change their scripts, operating systems change, and cheaters change their methods. So yes, we have to make updates, and sometimes it doesn't work out as we meant to. We have already acknowledged the issues with 1.6 and that we are using 1.7 to fix them. We aim to prevent this from happening again.
We have communicated heavily about all of this on our Discord server over these last few months. If you're not already in there, I highly suggest joining: https://discord.com/invite/mtasa