I’m quite ignorant in this subject. What happened?
There is a lot to it but essentially they transformed 2 arts into limited sports to the point where most Judo and Tae Kwon Do clubs now only focus on the Olympic sport rather than the full art. Basically a big part of the techniques have been taken out to fit within the Olympic rules which are more restrictive.
For instance in Judo the wrestling-type moves such as
kata guruma (shoulder wheel) and
morote gari (two-hand leg reap) are now illegal, so most clubs don't even practice them as they're not legal techniques under the Olympic ruleset. The real reason behind those techniques being illegal in the Olympics is because there is already greco-roman and freestyle wrestling so they don't want Judo to look too similar.
This also means that kata and self-defence aspects of the art of Judo are not really focused on anymore, only the competition aspect.
Same thing happened to Tae Kwon Do where now most dojangs focus on the Olympic sport rather than the art, and the art is actually by far a lot more efficient than the limited Olympic sport with its many rules. For instance hand techniques have diminished because of the Olympics. Another one is how Tae Kwon Do used to be more full contact and techniques scored if they landed and did damage, but the Olympics didn't like full-contact and preferred implementing electronic-scoring where it's about touching to score rather than throwing an effective technique with impact. Basically now it's a watered down version of sport Karate.
I can only imagine that if Kickboxing got to the Olympics it would be with a limited ruleset and more likely than not point-scoring rather than full-contact. This basically means that a lot of gyms would then adopt the new Olympic ruleset and train specifically for it in order to have state sponsored competitors within their gym and therefore having their gym state sponsored. Then this means more and more gyms focusing on the new Olympic ruleset, and before you know it there are heaps more competitions and competitors for Olympic Kickboxing rather than real full-contact Kickboxing.