- a lot of them are playing in a strong club context, so their maximum is also limited
- these people play bad contracts (even against the best opposition) better than most of us do.
Now, I'm sure they get better at playing bad contracts at least partly the same way I claim to (by bidding lots of them); and frankly, low-level partscore defence is the hardest part of the game (it is just too easy to make the slight mistake that turns the horrible result they're booked for into A+), but still, agreeing to open more and more average hands requires a change to one's responding structure, leading structure, et al. And doing it without agreement - well, that's got its own set of failure modes as well.
As far as the OP goes, in my area at least, that's an auto-open. "11s with an Ace" is "tell me why I'm *not* opening it"; and the ace in my bid suit, which is a 5-card Major, trump any reasons you might come up with to not open it in my book. If partner's expecting 13, well, we'll get to a lot of bad games (played by me; and a lot of +170s played by partner) until we sort this out; but as I said, in my area, anybody I'd play with won't expect 13!