True, but partner miles don't count. If somebody gives you 300k banked miles on AA, they count towards Lifetime levels. On UA, you actually gotta fly.

UA's system keeps the perk a big more exclusive - flying 1MM is a heckuva lot harder than accruing 2MM from all sources - but the side effect is that AA miles are worth a bit more in the "secondary market" than anything else. If I were a merchant wanting to bundle FF miles with my products - whether I sold cell phones, flowers, or whatever - I'd want to bundle AA miles if my costs of obtaining them were the same across carriers. To an end user, 1 partner AA mile is worth more than 1 partner UA/DL/CO/NW/US mile because it buys a slice of that lifetime status in addition to a slice of a free flight.