Indeed (although occassionally you get a board where almost every resistor is one of the strange E96 values for not really good reason).

I am also convinced that a lot of transistors are chosen because that's what the designer happened to have in stock :-). Yes there are critical ones, but I could tell you some good stories about substituting all sorts of transistors with 2N3904s and 2N3906s and still having the device work _perfectly_.