Adobe is bringing in more revenue than ever with their subscription model. Users are obviously willing to pay for it if that wasn't the case. No signs of them going under any time soon. Nor I'm guessing Microsoft even if they switched completely to subscription model. They dominate the enterprise environment and will likely continue to do so.
WIN 11 is basically just a rebranded version of WIN 10 with new interface and updated security requirements. The kernel is basically the same as WIN 10 for compatibility reasons. In fact, our chief endpoint support tech says he comes across components in WIN 11 still labeled as WIN 10.
If you're running WIN 10 with hardware that says does not qualify for WIN 11, you can still upgrade it manually. You just can't do an automatic upgrade. In any case, you have until mid-2025 end-of-life for WIN 10 support. The question is whether you want to get WIN 11 while it's a free upgrade, or pay for it later.
There is always a risk of running outdated OS or software no longer supported with security patches. As one might recall the WannaCry ransomware infected over 70% of WIN 7 machines through an unpatched vulnerability. Hackers are just too sophisticated and organized these days. Even to the point of running their own malware cloud services anyone can rent.