If it followed the product's success, products that are going through a bad patch, or are going downwards, would not be able to attract good executives, when arguably they are the ones who need the best executives, relative to products that are doing well, which on many occasions can sustain themselves purely on momentum.
This is further complicated for non profits which cannot use ownership stakes as an incentive either.
I may be a naive person who generally detests the organization chart gymnasts, but I honestly believe Mozilla would be better off if they just got rid of all C-suites and handed that cash to their developers to do whatever they want. So many open source projects are hugely successful without a CEO. Why would Mozilla be different? Keep the cash for the devs, and it's already miles ahead of any other big open source project financially!
For countless years they've been handed some 400-500 million(!) for "free", just by keeping Google the default search engine. For a conventional company, this kind of money requires a massive operation, customer base, etc.
Mozilla just gets a check. Half a billion for free. And then pisses away this money on projects where most are questionable, have no impact, etc. All the while the user base shrinking further and further, for over a decade now.
If that is the situation, it seems pretty reasonable to me to just get rid of leadership altogether. Let the tech people figure it out, it's not like they can do worse.
Let's not forget the ridiculous pay for the executives which has been shown to not correlate with revenue (or anything else):
https://calpaterson.com/mozilla.html
I give to the Thunderbird fund every year but have not given to Mozilla for a long time!