If a startup is riding a hype cycle and is one of two leaders in the global industry with unreal growth numbers, they can IPO whenever they want. The incentives lean toward doing an IPO before the hype runs out, not delaying it.
If they were worried about running out of VC money, going to the public (the P in IPO) would be the move.
Companies don't actually have to go public quickly or even at all, even though that's been drilled into us as the only goal of every investor-backed startup.