They must really love the music then, they sure as hell aren't moving for the better housing prices.

I'm not at all in the Amsterdam EDM or hardstyle scene (just not my music), but I had indirectly got the feeling that it was slowly declining (ADE excepted), I could be quite wrong though, maybe they're just all in NDSM or something.

Hardly. Amsterdam is comparatively small city = much smaller audience. You can se the stability of the scene in how often clubs close down. Just recently De School closed (now it should be reopen again under different management/name). Some of the Berlin clubs have been open and solid for 20 years.