Hmm… my memory may not be the best but apart from WinAmp almost every other app kinda stuck to the OS? ;o
So, same thing as today then?
Yes, except it was much more colorful and vibrant. We had pixel art instead of the the deliberately-monochromatic committee-directed stick-figure horrors of today.
Correct, nowadays it's accidental and boring inconsistencies, because they're all trying to be more minimal than the other app.