I'm also surprised they haven't tried to create commercial mail and communications products. Thunderbird used to be one of the best options out there, and they could easily spin this off into a SaaS and self-host product on the server component. As much as I hated Lotus Notes, something between Lotus Notes, Outlook and MS Teams could be something great and that the Mozilla org would be in a good position to create.
I know they may have good reach with the VPN service as well... I'm unsure how they can reduce security, qa and release management people when orchestration, automation and verification are such huge needs.
They get enough income from search (for now) that they could concentrate on best of breed tech, build mindshare from that, then re-introduce marketing for critical mass.