Most people/companies aren't Google, but as you say they assume that if one or more of the tech gigants (or other very public tech companies) are doing something, then it must be good.

Often the focus is extremely weird. When people noticed that WhatsApp only employed something like 45 engineers, then most assumed that it was because they used Erlang and FreeBSD. The thought that maybe their success was do to hiring the very best engineers and paying accordingly is less attractive.

Monorepos is just a another item to the heap of things that may be a good idea, but it depends.