https://gonintendo.com/stories/350214-the-snes-playstation-would-have-had-a-super-fx-chip-built-inside

Not only would the chip (which powered games such as Starfox, Yoshi's Island, and the SNES port of Doom) be used in the planned CD add-on for the SNES, they considered building it into the North American base SNES as well.

If it had been built into the US SNES it would've completed demolished the Sega Genesis in performance even moreso. They probably should've gone for it. The Japanese SFC could've continued on with the FX chip built into the cartridges.

I would have really loved to see what the SNES CD would have been, what kind of 1st party games would have been made for it. But I guess it was just not meant to be. I do wonder if they would have slightly updated the SFX chip or a stock one.

I think its quite probable they would've increased the clockspeed over the original FX chip, as they did for games like Doom and Yoshi which used one clocked x2 faster than the Starfox version.

Reminds me of 32X CD games.

Things like CD attachments or the 32X really fascinate me...
So many peripherals never live to see their potential realized...

Well. The SuperFX chip was a RISC CPU, so could have been used for anything, even non-gaming tasks... Although it did include a few extra instructions for graphics duties.
I think Nintendo made the right call not including a CD attachment or SuperFX chip with every console sold, keeping it simple is often the best way to go about something.

Good idea to not include one specific chip so we could get all the more specialized chips over the years.

The SA1 was like a new main cpu with 3x the clock speed. Blast processing achieved.

https://en.wikipedia.org/wiki/List_of_Super_NES_enhancement_chips