> they earned their options
Yes, and that option expires in 3 months after departing... In the same way that publicly traded stock options (ie calls) typically have expiration dates.
Part of the conflict here is that "options" aren't "shares" -- the option, including all terms (such as execution windows) are what is earned. Everything is known upfront. If you wanted comp to be around shares, then just issue shares via RSPA and deal with the cap table consequences and extra legal wrangling.
This entire "problem" is caused by tax code: you owe the IRS on gains from option conversion, even though the underlying asset is entirely illiquid and frequently non-transferrable. Sounds like a "real" solution is to lobby for tax code changes.
EDIT: to be clear... I'm not saying I agree with short expirations after departure. But there needs to be a clear distinction between shares, options, and 'intent'. Clearly the existing two ways of comp are lacking since there are either tax consequences (options) or out of pocket employee expenses to purchase (shares).