Mozilla is basically known to focus on everything other than what they're supposed to be working on. Their browser. Whether that's building an OS, some random social cause done crudely (i.e. questioning YouTube), or some other thing.
That's what led to the decline of Mozilla Firefox, their only actually successful product.
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Starting new projects is fun, I guess. Milling away at what is actually relevant to them (and what users are actually interested in) isn't as much. Then, at the end of the cycle, they just close those projects anyway.
There is even a speculation that Mozilla deliberately made their browser worse because they have received money from Google. That is how poorly run they were.