FxOS at its height was an absolutely huge resource and personnel commitment; I seem to recall it being half of MoCo, maybe more.

Mark Mayo, then SVP Firefox, was quoted in a 2017 interview with Walt Mossberg:

> Mayo says [FirefoxOS] took the focus off of Firefox. “It was close to a bet-the-farm effort”

Cite: https://www.theverge.com/2017/1/25/14376710/walt-mossberg-mo...