Re:cost of status, the point is that money is fungible. Paying full price and getting a rebate is basically the same as paying a lower price unless you have cash flow issues (ignoring time-adjusted value of money due to such short time periods). Even though the out-of-pocket expenses for the particular flights that contribute towards status remain the same, the total out of pocket expenses on all flights throughout the year drop. If your have to take 10 equally-priced flights in a year, or doesn't matter if you get a 10% discount on all 10 or if you pay full price for 9 and get 1 free. Either way you are paying 9x the price of 1 flight.
RE: status with other programs: Other programs definitely earn a lot less RDM but if you are serious about earning more than you can use this should not be a consideration. RDM that you don't use have a value of 0! Having said that, a 550k balance is really not that much. My balance will be around that at the end of the year! Once it gets to the millions and looks like it will never drop below that, it might be a serious consideration though.
With the amount that you fly it might be worthwhile to collect top-tier status in as many major alliances as possible. This is useful even when redeeming on AS. Eg if you accrue to some OW airline and become emerald, when you take an award flight on any of the OW partners you can put in that FF # instead of your AS number and get emerald benefits. There is some value there when you are not flying F (eg a route within Asia with no F cabin). AS has partners in all 3 major alliances to they could technically all have some value (but OW would be the most valuable).
Also having some miles in the program of a major alliance gives you a lot more redemption options. Yes, you might be earning at 1/2 or 1/3 the rate, but, again, if the AS miles would go unused this should not be a serious consideration. You should gladly trade 3 AS miles that you will never redeem for 1 UA mile that you can redeem on a non-AS partner -- the flexibility has value.
Just a different possible strategy to think about... 500K AS + 500k UA might have more value than 2M AS.