[sweetjazz]

Serious reply: this is probably mostly variance. Other likely factors include:

(1) game composition has changed significantly -- not necessarily tougher but different -- perhaps your playing style was better suited for the other games (i think hand reading has become more important than it used to be)

(2) possibly poor table selection skills -- there are still plenty of good tables but depending on your style it may take more time to find them

(3) tilt -- often running bad is compounded by poor judgment. besides obvious spew tilt or bad calls, is it possible that you are staying longer in bad games to try to get back to even for the session/day/week/month? are you devoting mental energy to thinking about the bad beats you have taken and is that distracting you from getting good reads?

(4) multitabling -- are you playing too many tables? are you relying too much on PA HUD stats to make decisions?

(5) studying away from the table -- are you still thinking about hands a lot away from the table and are you looking for ways to exploit your opponents' playing style?

I think games are still very beatable, but they now require both discipline to make routine plays consistently (which was often all that took to be a winner in the early days of online poker especially at lower limits) and the ability to analyze close decisions well fairly consistently (which has always been a good skill, but is more necessary now than it has been in the past).

All that said, I imagine at least 80% of the discrepancy is related to variance. But that is something you can't control. You may as well use your downswing as motivation to improve your game, because even if you are still a $100/hour winner, that doesn't mean you can't get better.