If you are a smaller Stripe equity holder, you're feeling "Wow, I would've sold last year and made a killing compared to the prices I'm getting now!", and it's not unreasonable that this same liquidity event would've commanded higher prices a year ago.
Of course, in reality, it's not a given that any individual would've timed the market perfectly. But because nobody had the opportunity to try, everyone feels like they would've been rich(er) if only they had been allowed to sell.
Common vs preferred stock only matters in the event of same or liquidation if a company - preferred is paid out first. At IPO, both kinds of shares convert into the same public class of stock (with the rare exception of founders creating a special class of shares for increased voting power).
Functionally dilution should be considered in the full context of the financial outcome unless we are talking about voting rights and I wasn’t. For small shareholders the only real value of stock is money. If it is worth less money then its value has been diluted.
Obviously no one is literally forced to sell. Is this really that hard to understand? This entire thread is about how by not going IPO, the employees were unable to sell. I'm sure they would have preferred to sell a few years ago instead of paying less taxes now.
It also seems that some employees' options are expiring, so while they aren't literally forced to sell, in reality, they are.