"Bothered" is a bit of a strong word there. When the company I worked at had 30 engineers, fewer services, and fewer lines of code, I did know how almost everything worked. Now we have over 3x as many engineers, and enough services such that it would be a full time job and then some just to keep track of how everything works.

Fortunately we do team/product-based on-call, so people are (for the most part) only responsible for services they work on or at least are familiar with.