I don't think Star Fox would be possible on the SNES if it didn't use the Super FX chip.
Here is a list of SNES chips and games using them:
I will be damned that Pilot Wings is on there, however I will say this though. What does that say about the SNES alone with out the chips? Now I agree with you 100% about Star Fox, however I donot think the games were as fast as teh Genesis Games. I donot think SOnic could run on the SNES, but then again most SNES games could not run on the Genesis. As I said the SNES did use alot of chips, granted, but I think the Genesis could prove itself on its own. I think in many instances multiplats were better on the Genesis, and others. I think the Genesis port of Earthworm Jim is better then the SNES, but then again you could and say. I am saying they were on equal levels
SNES without chips could do some mighty good graphics too as seen in Donkey Kong Country. The speed of Genesis games is not so much a matter of the CPU as is of the programing. You see the "blast-processing" which was suposedly evident in Sonic 2 was, in fact, just a trick where Sonic moved out of the visible area and gave the impression that the game was faster than it actually was. There were fast games on the SNES too. The only occasion when the Genesis really had the upper hand over the SNES were games with a lot of going on, i.e. for example with loads of enemies on screen at once or in games with multiple background layers like the Thunder Force series. I can see SNES having problems running Thunder Force IV and Thunder Force III was faster on the Genesis too. But that problem could easily be solved with aditional in-cart chips which would be used to accelerate the graphics. After all, the SNES could handle games as complex as Doom if they used the chips. Earthworm Jim may be better on the Genesis since it was developed for the Genesis and later ported over to the SNES. However, Earthworm Jim 2 was better on the SNES, as were Super Steet Fighter II, Mortal Kombat II and so on. Genesis and SNES weren't equal when it comes to tech. SNES could display more colors, more advanced effects (like Mode 7), supported in-cart chips (Genesis only did this for Virtua Racing) and had agruably better sound. The only thing where Genesis was better was, like stated before, the CPU speed.DKC was done with pre renderd graphics, other then the colour count, the Mega Drive could have probably done a similar thing.