An IPO is a loss of control for founders (now you need quaterly narratives & slave to markets). If you can avoid it somehow, you do. Stripe could avoid it because of great secondaries and good money in the bank. I don't think they regret it? Employees might, but as a founder private >>>> if you can.
are they doing buybacks or dividends? what is driving secondary market sales if there is no expectation of IPO?