Another factor at play is the age at which people are getting baptized. This year I saw, for my first time, a 6 yr old get baptized. I don't think there's anyone who's forgotten the stance on infant baptism (even though they haven't talked about it in a while) so they're running out of younger kids to get baptized in order to pump up the numbers. I predict a drop in baptisms in the next 5 years or so as they run out of younger and younger kids to baptize. The baptisms have already declined significanly, and it's only going to get worse. Of course the R/F won't notice, because if there's a decline they only print this year's numbers, and even 100k baptisms sounds good as long as you don't mention that it was 300k not too long ago.
Another thing that's already been mentioned is consolidating branches. If the R/F compare numbers from a couple years ago for the US, to now it appears to be a huge increase. The problem is that a few years ago, the US was only the US (and I think excluded Alaska) but now its the "US Branch territory" which includes several new places. It seems like it might be difficult to keep up the consolidation of the numbers without people noticing, but there doesn't seem to be an end to what the R/F will swallow. Maybe in a few years Mexico and Canada will be in the "US Branch Territory."
They definitely seem to have declining contributions. Also, because the "growth" in developed countries comes almost exclusively from born-ins coming of age, the best they can hope for is a lagging growth in contributions - that 6yr old that got baptized this year isn't going to be making any meaningful contributions for another 10 years. But as we know, fully 2/3rds of kids eventually leave, and that's probably without ever making any significant donations. So 2/3rds of the growth they're reporting is really just kids filling seats they're not paying for. Those seats indirectly cost money...without those kids taking up space, they'd likely be able to consolidate more congregations and sell off a few more KHs. Not to mention the money towards utilities to operate the extra KHs that means donations that aren't getting sent in to 'mother.'
They're definitely not in a great place. That said, they can probably last a good while longer, so as much as I (and I'm sure many others here) would love to be able to just wait until they crumble around me so that I don't have to make an exit, that's probably not a viable option. I'm not waiting 20 (or even 5) years for them to implode.