[grouchie]

I would venture to say that the main reason is because Limit ring games have been more plentiful and have been around longer, so that is what most people learned to play.
No limit ring games really have just started to spring up massively since the Money Maker WSOP.

So, most people who's main game is limit will stay with their main game while clearning bonus's.

I would think that the percentage is realitively small of people who switch their main game during bonus clearing.