Then I bought a 3DFx Voodoo card and started using Glide and it was night and day. I had something up the first day and every day thereafter it seemed to get more and more capable. That was a lot of fun.
In my opinion, Direct X was what killed it most. OpenGL was well supported on the Voodoo cards and Microsoft was determined to kill anyone using OpenGL (which they didn't control) to program games if they could. After about 5 years (Direct X 7 or 8) it had reached feature parity but long before that the "co marketing" dollars Microsoft used to enforce their monopoly had done most of the work.
Sigh.
D3D was a terribly designed API in the beginning, but it caught up fast and starting at around DX7 was the objectively better API, and Microsoft forced GPU vendors to actually provide conforming and performant drivers.
For audio everyone was using 3rd party tools like Miles Sound System etc., but even OpenAL launched around 2000 already as an OpenGL companion. Video had the same thing happen with everyone using Bink which launched around 1999.
In comparison using OpenGL was a lot nicer than anything before probably DirectX 9. At that time in DX you needed pages and pages of boilerplate code just to set up your window, nevermind to get anything done.
Advanced GPU features of the time were also an issue, OpenGL would add them as extensions you could load, but in DirectX you were stuck until the next release.