I have seen people reinstall windows 10 just to get this strawberries program to work. That is not the signs of a well made program
You have to understand a couple of things here...
1. FF7-PC was released 22 years ago, when Win95(!) ruled the roost. The mentality (for lack of a better term) of the 9x codebase was totally different from NT (and remember, XP was just a theoretical target in Microsoft's eye at this point.. 98 was about to go gold, and the abomination of ME was going into early dev). Therefore, assumptions about the system environment (permissions in particular) that were true then are no longer valid. Hence the constant "Run as admin" and "Run at 640x480" type issues.
2. InstallShield was a kludge then and still is today. More 20 year-old assumptions that no longer hold true
3. As Microsoft continues to fix bugs and improve the overall OS, more tricks and techniques that used to work, won't. Many are the installs that were broken on Patch Tuesday.
4. Nobody has the source code to go back and fix what might be broken. Not even SquareEnix. A bug that might have been perfectly harmless back then could cause modern OS protections (ASLR, DEP, W^X, etc.) to fault out and crash the program. The mods, injectors, and what-not you see here are the result of a bunch of people poking and prodding at finished object code and trying to figure out (very successfully, for the most part) how it works, then slipping their own hooks in, which, not-so-coincidentally, is also how a virus works. Cue problems with anti-virus programs in 3... 2... 1...