1. DL (and now some other USA legacy carriers) is revenue based for redeemable miles but still uses actual miles (with 500 segment minimums and percentage bonuses for certain more expensive fare classes) plus a separate revenue or affiliated credit card spend requirement (with waivers for foreign addresses) for status. UA is very similar and AA is seems to be following.

However, certain foreign carriers have long used revenue for status, notably LH/LX and SQ and IIRC also QF. One can also argue that the generally low percentage earnings for redeemable (and status) miles on many foreign carriers is really a proxy for having a revenue based awards program, in contrast to the USA former legacy tradition of giving 100% redeemable miles for every published coach fare.