It's just like old music. People have been making music since the dawn of time, and the ratio of good to shit music was relatively constant. The only thing is, shit music tends to be forgotten over time, whereas the greats still survive.

People that are into old music, regardless of the period, are almost by definition listening to a curated bunch of greatest hits. Ditto for retro gaming: the by-the-numbers, derivative or unplayable crap is long forgotten.