Mozilla claims over 700 of their 750 employees work on Firefox. It's a bit harder to find out the number of people working on Chrome. The founding director remarks that there were 40 engineers working on Chrome mobile in https://mdwdotla.medium.com/some-thoughts-on-running-success.... That's obviously just a slice of the whole team. Search results suggest a range of numbers between 23 and 500. There appears to be about 12k in the whole department building Chrome, Android and the other software shipped to users. From all that you can extrapolate that there likely isn't a huge disparity between number of engineers on both browsers.
I genuinely don't believe that 700 people work on Firefox because if that were true the quality would be much different and things would be done faster.
If there's 700 active developers on Firefox then they sure as hell must be having a great time "working" remotely. The development pace of Firefox is atrocious.
