For starters that'd be a reason to cut cost and allocate an increasing proportion of current revenue into a diversified investment portfolio to eventually gradually shift towards being able to at a minimum know they can cost-cut and survive of that investment return should they need to.
If I was aiming to set up a company like Mozilla, I'd want all earnings to go into such a fund, and all costs to come out of buffered investment returns... Yes, significantly slows down the rate you can spend, but it also significantly increases the odds of longevity and independence.
Of course that presumes the goal is to build the organization, not to get personally rich off it.