Firefox built-in Tracking Protection out of the box works well enough I can imagine a lot of other users feel their needs are met without additional add-ons.

I know I don't have any additional add-ons installed, but I'm already getting nagged so much by websites to "disable your adblocking", with many confused to thinking I have something like uBlock Origin installed and only a few so far realizing it is just Firefox. (Those that do sometimes requesting I reopen the page in Chrome seems to prove the point that Firefox is doing some things right and Chrome not at all.)

How much do you trust add-on developers? For the past 5 years I'm only using add-ons during recreational browsing. The market for personal information is just too aggressive to assume you're safe. I imagine this is part of the reason. Another reason could be that "power users" opt out of analytics right away, leading not only to skewed statistics but also awful UI decisions by Firefox, as they have to make their decisions based on the data they collect.

Do they include people who opt out of Mozilla's user tracking? Because ubo users seem more likely to do just that.