"Mozilla spends $200M on it per year" does not mean it costs $200M per year. Considering Mozilla overspends on everything else, it's not a stretch to think they might be overspending on this too.
> Considering Mozilla overspends on everything else
That something is repeated endlessly does not make it true. In fact, it's a signal of disinformation (which doesn't make it false). And when words are used like "everything", it suggests 'nothing' specific is really known. And even to the degree it's true, the inference is weak; the question is, how much does web browser development cost?
$200M seems reasonable to me. Comparisons I've seen make it quite a bit less than estimates of Google's costs, for example.
That bridge will be crossed when we get to it. Thunderbird improved substantially after Mozilla stopped maintaining it. Thunderbird was held back by Mozilla.
Thunderbird began improving, as far as I know, after multiple post-Mozilla iterations, including returning to the Mozilla fold in a different relationship, which is where it is now. Its improvement was not correlated with the Mozilla breakup.
Mozilla and the Thunderbird teams knew, however, that a breakup was needed for both Thunderbird and for Firefox (Thunderbird compatibility requirements were holding back Firefox).
The reason was that Thunderbird was a low priority for an organization that has a much more successful application in Firefox. Low priority projects don't do well; the organization naturally structures, invests in equipment, hires, manages, etc. for the high priority. You want to be a high priority wherever you are - better to be the big app in a small org than a small app in a big org (as a very general statement).
If you don't know these things, why make up sh-t about Mozilla? What do you get out of it?