What’s the count for us is how many gamers (especially our “target gamers”) are using a given system.
It’s only approx. 6% of Steam users (who agreed on the survey) are still using Windows 7.
https://store.steampowered.com/hwsurvey/
Not all of them are necessarily a target for a visual-heavy 3D game. Actually it would be nice to have data combing given OS and hardware, i.e. how many users with modern GPUs use Windows 7. Or if people on old systems actually actively buy games - most of the Steam users buy only 1-5 games.
Less important if someone’s game is a simple 3D game.
Obviously, it just arguing on numbers. And doesn’t matter much, dropping support for Windows 7 should be properly announced ahead of release, so the developer could decide if it’s OK for him to consider an upgrade.
Windows 7 support could be sustained until the end of UE4, dropped by UE5 at the end of 2021. Most likely most of the active games would switch to Windows 10 for DirectX 12 gains. And still would be almost 2 years after dropping support by Microsoft itself. (that’s just my thoughts, though)