Google has very large applications, but also they are using static linking: imagine that you statically link all the possible dependencies in a single binary for each application. 300MB is not considered a large binary at Google actually, I don't know what is public but you may look at Table 2 in this publication for instance: https://www.researchgate.net/publication/314105281_ThinLTO_S...

I repro here some data, there is a bit more in the paper:

Clang 1.9k Files, 217MB (-g0), 3554MB (-g) Chromium 17.8k Files 706MB (-g0), 7544MB (-g) Ad Delivery 13.8k Files 1073MB (-g0), 7469MB (-g)

(this is the number of object file that are participating in the link).