Development costs are to blame and also share holders.
High profile games are getting more and more expensive to produce and (I know people hate this idea but still) having different platforms doesn't help either. When the gaming industry has a unified platform and devs can target gamers instead of specific console owners they will be able to do high profile gaming all over again.
Otherwise, budget games on Steam/XBLA/PSN target core gamers more than retail games.
Edit: Not high profile gaming but less casualized gaming...








