> But over the years they’ve spent money on an email client basically no one uses, trying to make a social network, trying to make a phone operating system, and who knows what else. Just huge amounts of money going to what often looks like a complete fools errand. I understand Thunderbird but a phone OS?

Keep in mind that both Firefox and Thunderbird started life as an evolution of the original “Mozilla Suite” which itself was an evolution of Netscape Communicator, which included a browser and an email client. So originally both were part of the core mission of Mozilla.

Thunderbird failed to gain much traction though and it was later spun off — it is now developed by a separate company (a Mozilla subsidiary).

> but a phone OS?

Yes, this does not make much sense to me either.