Multitabling question

In theory, couldn't a winning poker player maintain the same average BB/100 rate playing less tables at a higher limit? For example 4 tabling 5/10 tables verse 8 tabling 2/4 tables? Granted, the players might be better at 5/10 than 2/4, but you could also pay better attention with less tables, and possibly play better.

Something has to be wrong with my theory or I'd think more people would do it.