Little confused about limit and NL live winrates, bankroll, and EV

[ChicagoTroy]

Bear with me because I'm a limit player who has vague concepts of NL BR/winrates but can't make sense of some behavior I see at the casino.

I play at a local casino where the highest limit game is typically 20-40 and the highest NL game is 5-10 with a $1K buy-in.

Given that, it would appear that a 20-40 player needs a BR of about $12K, while a NL player needs $20K. However, given the slower pace of NL, it would be tougher to overtake the a 2 BB/hr. a very good 20/40 guy could pull out of that game with a smaller bankroll.

Despite that, I see a lot of 20/40 guys migrating to the NL game. Granted, the fact is many are losing players and no BR is sufficient, but wouldn't a solid 20/40 guy be better off, from a strictly hourly rate perspective, playing limit?

I may be underestimating what a solid hourly blinds/hr player can win in a weak game.