There are plenty of pools to choose from they just have low hash. If all the big pools start colluding there are already places to go. Plus necessity is the mother of invention, more pools would spin up. To dominate mining you have to operate the hash. Many many people operate the hash. Xmr had 3 pools essentially, there are many more large pools to choose from with bitcoin. If the use of exchanges is required then doesn't xmr have a much bigger problem? Only exchange I know of is kraken. Even if using Bitcoin p2p is illegal, it still can't effectively be stopped.