Compare instead Google's average products (y'know — the kind they eventually shut down) to the largest FOSS competitors in those same verticals.
For example, compare Google Reader at its peak MAU, to the current #1 open-source RSS reader app.
Or compare Google+ to, say, Mastadon. (Mastadon is a FOSS Twitter knockoff whereas Google+ was a Facebook knockoff, but I think the point stands.)
Or, for a painful one, compare Blogger to Wordpress! (Okay, maybe that one's not fair, since Wordpress is a real company that can hire product managers. But most WP development is still random FOSS developers scratching their own itches.)
Or compare Google Code at its peak to, well, anything. GitLab CE, GNU Savannah, anything.
None of these were failures of engineering. They were either failures of product management, or failures of budget/staffing — which is in essence still product management, since it's a PM's role to fight for the budget and headcount to get the job done.
(That's not to say all but the best Google products rot on the vine. IMHO Google are pretty good with steering their internal B2B engineering-driven offerings, e.g. GKE, Firebase, BigQuery, etc. Those are run a lot like FOSS projects, in that it's a combination of internal engineers scratching their own itches, and customers directly filing bug reports, that determine what gets built. It's the B2C products, and the marketing-driven B2B products — where in either case the engineers involved might not have the problem themselves, and the customers might never directly engage with them in troubleshooting their workflows — that tend to falter.)
> There is libreoffice, but even on it’s best day it’s not doing real time document editing/collaboration with 10+ people on opposite sides of the planet, and that is the Google Docs bread and butter for instance.
If that's your only requirement, then the FOSS project https://etherpad.org/ that Google acquired to build Google Wave off of (and then later dis-acquired) satisfies it pretty well. These days it's even kind of a word-processor! (Originally it was just a multiplayer <textarea> with per-user text background colors.)
