Your misunderstanding leads you to believe that somehow an option is worth a lot less than a 1x participating stock, and it's not.
Again you side-stepped the comparable:
As an employee, even with a '90 day exercise window' which would, you chose for compensation (or what would most people chose?)
1) the ability to invest $1M for a bunch of preferred shares; or
2) a bunch of ISO's at a low exercise price?
Everyone will take the ISOs due to their riskless nature, now why would they take option 2 if it's so 'inferior'?
A 1x participating preferred is a perfectly rational type of financial instrument for VCs, and some type of ISO is actually well aligned for staff. Though things might evolve here and there, there is zero chance that the 1x preferred aspect is going away.