Firefox has a long history of marketing itself as privacy-focused. This was not about privacy. This was not about "making things better for people on the Internet," it was about a few individuals enriching themselves.
The outcome of this scheme is less privacy for the consumer. It doesn't matter that Firefox doesn't include exact identifying information. It still identifies demographics and other specifiers that can be used to target groups and their habits otherwise it would be as useful as an impression counter. This whole scheme is contradictory to how Mozilla has been portraying itself and the opted-in default is a 'fuck you' to anyone who cares about this. Putting the word privacy in the name does not mean it's private. PPA changes nothing with regards to the advertising industry.
Saying ads are here to stay so you have to accept them or die, is an absurd false dichotomy.
The last Mozilla executive had a salary of over 6 million before they replaced her with the new CEO making these changes. The owners of Anonym (previously Meta executives) made money when Mozilla bought them. There is still money to be made in non-profits.
They didn't sell your data before, they didn't die before. The idea that they suddenly have to start doing it now or else is incorrect.