Sound systems are a bad analogy. A decent amp and a pair of speakers can be had for next to nothing and the tech hasn’t changed that much since 1970. If the parts haven’t broken due to age a vintage set can sound very very good and be picked up second hand for less than 100€ or $

Isn't it the same for gaming? You never need a new computer to play old games. They can't even take benefit of the improved technology.