That's a good point, that there are other regions that want the same.

However at some point I feel their hand will be forced, much like Britain was forced to grant independence to all those former colonies, after the movement started. The few that remained looked really bad, so they were granted official independence with some under-the-table deals to keep the benefits Britain enjoys largely intact. Spain could've put themselves in a similarly advantageous position, but instead they chose to go hard-line and now they may wind up with nothing if Catalonia actually leaves.

Good point about the divide and conquer too. Having several different types of people fighting to maintain control is a great way to keep people distracted and fighting over meaningless crap, while both sides have their lives run by the same groups of people, some without even realizing it.