Most of the Etherpads are ex-employees of Google that left to start their own company. I don't see any other way to interpret your comment except that you are suggesting that they should've quit running AppJet a year ago (since the option to be bought didn't seem to be available then) and interviewed at Google to get their jobs back to work on GWave at an early stage, but without the added benefit of having millions of dollars worth of Google stock. This seems quite bizarre.
My point is that if they wanted to build their own company they should remain committed to the product they built, and find a better support model for current customers/users than shutting down without notice.
I do not begrudge them making money at all. But one reason that they have "millions of dollars worth of Google stock" is because they offered a service that people adopted and paid for. I think they have more of an obligation to customers and users than the initial announcement indicated and I worry that not taking better care of customers in the transition makes it hard for other startups.