[Maxatar]

I have to disagree with you about MMX. It's possible a lot of software didn't target it explicitly but on Windows MMX was very widely used as it was integrated into DirectX, ffmpeg, GDI, the initial MP3 libraries (l3codeca which was used by Winamp and other popular MP3 players) and the popular DIVX video codec.

[conductr]

Similar to AI PC's right now, very few consumers cared in late 90s. Majority weren't power users creating/editing videos/audio/graphics. Majority of consumers were just consuming and they never had a need to seek out MMX for that, their main consumption bottleneck was likely bandwidth. If they used MMX indirectly in Winamp or DirectX, they probably had no clue.

Today, typical consumers aren't even using a ton of AI or enough to even make them think to buy specialized hardware for it. Maybe that changes but it's the current state.

[bombcar]

MMX had a chicken/egg problem; it did take awhile to "take off" so early adopters really didn't see much from it, but by the time it was commonplace it was doing some work.

[martinald]

ffmpeg didn't come out for 4 years after the MMX brand was introduced!

Of course MMX was widely used later but at the time it was complete marketing.