I believe even at FAANG-like companies, only a lucky minority is involved at that level of scale. Most developers just use the available infrastructure and tools without working on the creation of S3 or BigTable.
This famous blog post [0] suggests that the default behaviour at Google at least is for everything to deal with massive scale. Doesn't mean everyone is involved in creating massive-scale infrastructure like S3 or BigTable, but it does mean using that kind of infrastructure from the start
