This has not been true anywhere I've worked at. There's usually tons of tribal knowledge, internal tooling/software, external software thats just rarely used, and code base quirks. None of which you'll find on google/stack overflow.
I did. 90% of their questions were 1 Google search and 1 stack overflow click away.
Your company might be different, and sure some knowledge of system is only available from seniors, but your company still will have enough documentation, if a search for keywords in it likely to get results.