I agree with Adam's post and intensely disagree with A16Z's post on this topic.

I don't think companies should take back stock compensation on a technicality. It'd be silly to even discuss taking back cash compensation when someone leaves a company!

I appreciate Adam starting this trend years ago.

The answer here is for you to convince VCs and other investors to support this, publicly, and tell founders that they won't be punished for this on future fundraising.

Hearing from A16Z that they don't support this is a big negative signal to any founder.

a16z is a major investor (growth round resulting in a board seat for a16z) in many of the companies that have extended vesting periods, such as Coinbase, Pinterest, and Asana. So I doubt they block companies from doing this.

Notice the companies you listed. They are/were the absolute hottest companies when they raised their rounds, and are still some of the most prominent startups around.

Put another way, they have negotiating leverage.

The ones with the leverage (including YC backed companies) have to lead the charge to change the status quo and "the standard". The average startup doesn't have the leverage to do something nonstandard. The fact that YC has come out in support of 10 year vesting periods and is making it a standard is a massive step forward.

Barely any companies even have extended exercise windows, so you can't go around excluding companies from the list because "they don't count". Also your logic is almost circular, because a16z tends to only invest in hot/great companies, by definition.

You can go down the list: https://github.com/holman/extended-exercise-windows. Many other companies have a16z as an investor. Tilt and CodeCombat are two of them.