The US airlines have collectively decided not to offer that kind of mileage rebate anymore. (Well, WN and then DL started it, and everyone else followed suit). That’s the crux of the issue between AS and AA, incidentally. AS has been holding out hope that it can maintain a mileage-based program instead of a fare-based program, but, to do that, they ended up having to gut the redemption rates for AA, since AA wasn’t interested in paying AS a bunch more for its members than it’s paying for its own.