Tyson did but he's a lot faster than Mo, again that's just what Botha said, either way getting hit by either Tyson or Mo wouldn't be great! Also Botha did throw kicks every now and then, he could take kicks much better than the average boxer too.
I think old school fancy pants kickboxing actually was quite popular in the 80s. As for the more modern style kickboxing, theres a parallel universe where K-1 actually made that Sapp/Tyson fight, ran tons of shows in the US and found multiple viable American stars, and ended up occupying the position the UFC would go on to occupy.