I appreciate your pesonal perspective as an employee of the company I used to admire a lot. It looks like we disagree on the fundamental premise
To me, the golden age of tracking is over and the privacy of the user is the new gold standard. It doesn't matter that Firefox needs telemetry to survive (and the empirical evidence of Firefox still losing users left and right does not help that case), if it is going to violate someone's privacy over it.
It also does not matter what its privacy policy is (and they can change), the moment Firefox transferred user's personal information, which is the IP address, without their consent, it took away something private from them, that can potentially be used in the future against them.
Here is an analogy. Would you accept telemetry in your apartment or a house, that is built-in and enabled by default, without your consent? Would you freak out that it exists once you find out?
The builder will then try to explain they use it only to improve homes they make, for example to understand what rooms you use and how, and that without it, they would not survive on the market because their main competitors are using it too. Would you care about that or you would seek to find an apartment elsewhere?
The browser is no different. It is the most intimate tool we use in our daily lives. People are fed of our data being used without our consent.
A privacy respecting browser simply can not allow itself to have telemetry by default. Meaning Firefox simply can not call itself privacy respecting if it is transferring user's private information without their consent, by default - no matter what the economic or business justification are. If a browser is choosing to have telemetry for economic interest, it loses the privilege to call itself privacy-respecting or 'a force for the privacy on the web'. Respecting privacy is digital, it is either 0 or 1, you can't be 0.7 privacy-respecting.
Finally, I don't buy the argument that telemetry is helping FIrefox at all. All that telemetry for the last 10 years or so and Firefox is down to less than 5% market share. It lost 50 million users in the last two years alone.
Perhaps Mozilla should consider becoming more user-centric instead and start listening to the users, instead of using telemetry. Go back to its roots of innovation and experiments, to the golden age of Firefox between 2005-2010 when we got Firebug, Ubiquity, Panorama and go back to product annoncements that excite user about the browser.