They actually did try to make it work at all frame rates but I don't think they were actually able to test it very well because the hardware, as you said, didn't do it.

A lot of games were hardcoded for a specific FPS. Even modern-ish ones!

Our local computer graphics prof hated this and set the loop rate random for the opengl idle function on our submission server. At one point it hang for 5 minutes between frames.

Brilliant move, must have been one hell of a smart guy.

I hate to say it, but fixed frame rates these days seem very 'lazy'? Obviously depending on use case and hardware.

I wouldn't call it lazy. All development is compromise. Especially game development.

If you know the game is only going to run on certain hardware, and you make the most money during the launch period of the game, it doesn't make sense to spend time, effort and money on something niche for the future.

Delta times make difficulty for games that rely on lockstep for multiplayer. It's why factorio, for example, is capped at 60fps and will slow down gameplay at slower framerates.