I'm personally fine with that. Mozilla Corporation (Firefox) remains the largest part of Mozilla.
As the cash cow, it will always receive what it needs, but it will also act as the vehicle for funding possible avenues of diversity.
Mozilla is never going to be independent off of Firefox alone -- that revenue simply doesn't exist.
I wish Mozilla had taken Proton's approach, but regardless, I hope they manage to throw something that sticks.
A fully financially secure Mozilla would truly allow their organization to shine.