Films that bring in hundreds of millions of dollars from the box office consistently manage to post up zero-dollar profits. (Screwing anyone who lacks the leverage to have demanded a percentage of revenue, as opposed to a percentage of profits.)

And yet, somehow, the funders keep bankrolling 'profitless' sequels after sequels.

As bad as the 1/9/90 split of outcomes for startups is for employees (1% of a good exit, 9% of slight profit/break-even, 90% of a loss), transitioning to your model will destroy the upshot of the 1%, and make the 9% even more contingent on your employer and funders not engaging in Hollywood accounting.

What you propose creates a colossal incentives for investors to turn the 9% case into an (on paper) 90% case - because otherwise, they'd be on the hook for a very large number of backdated salaries - the obligations for whom magically disappear if you structure the 9% case as a profitless exit.