> Yeah I think this is how it usually works, and yeah at $100bn valuation they are now 100% worthless, because investors get paid first, and there's no way they'll get sold or IPO for more than $100bn.

Not quite right? Because the raise-implied valuation doesnt account for preferences. The IPO could be for 50bn and the latest investors could do well given the preference stack of first money outs in later rounds.