I do think that:
A: They have PLENTY of money for quite a while.
They have fooled all the US congregations to give them more money each month than they would ever have gotten by having mortgages repaid.
They sold Brooklyn.
They have cut most of their costs.
B: They have a SOLID foundation of people who will believe NO MATTER WHAT.
C: That said - recruitment is only coming from KIDS getting baptized.
D: There is no way they can keep 8 million+ happy in the next 20 years as their promises continue to FAIL.
I think that in the next 10 years you will start to see a contraction as the faitful die, young ones want no part of it, and the AMAZING CART WORK (why didn't jesus thing of that 2k years ago) reaps NO rewards.