Unfortunately, almost all browser games rely on Flash. And a huge game, Minecraft, relies on Java. There's no way that either Flash or Java will ever go away.
I wish they would port their games to something else because I really don't want to put up with Flash anymore either. I've been playing a browser game for a long time, and despite having an i7 and 12gb of RAM, it still is super laggy, slow, and hogs most of my CPU. Something that produces very simple 2D graphics should not be taking more resources and running slower than PayDay 2 or Diablo 3 on max settings.