Sort of agree and disagree. The mathematical advantage obviously comes from their edge, and that is how they profit longterm. The betting limits are just a way of limiting their risk, which is a kind of advantage. They basically make alot of slightly +ev wagers.

If casino's didn't have max betting limits they'd go bust vs lucky/super bankrolled martingalers. Or at least encounter enough variance to mess up their operation

Without a max bet martingale looks fine, but there is always the possibility that you will lose every bet forever. Problem for the casino is that the edge itself isn't enough, they need to curb their risk ('overbetting' would lead their +ev game to be -ev).

Casino's love martingale (when they have the usual limits) since the bettor is turning over a very large amount of money, much more than a min bettor.