The contrast between the Uber and Google setups would be twofold. Google engineers weren't doing local builds anyway (unless they intentionally inflicted those upon themselves) because of Forge. The Forge builders already had 10000 CPU cores in 2010[1]. You can probably imagine how many cores Forge or its equivalent has today. Secondly Google doesn't suffer from the performance problems of a weird freeware VCS, because they don't use git or the git workflow model at all. They built their own VCS based on the workflow model from Perforce.
One funny aspect of Google moving development into cloud machines was that a decade before the process ran the other way. The desktop that was issued to most engineers was a production websearch machine turned sideways and stuck under your desk.
Google contains multitudes. Android, Chrome, and ChromeOS are examples of large Google projects that do not use Perforce and are routinely built locally.
Chrome, at least, is typically built in the cloud (I don't know about Android, though it would be weird for it to be the only major project that doesn't do this). It's not just that you can have beefier machines in the cloud (though that's a factor); it's also that you can have a shared cache of build artifacts for all your users, which makes most workflows a lot faster. See documentation: https://chromium.googlesource.com/infra/goma/client/
One funny aspect of Google moving development into cloud machines was that a decade before the process ran the other way. The desktop that was issued to most engineers was a production websearch machine turned sideways and stuck under your desk.
1: https://youtu.be/b52aXZ2yi08?t=1118