What do you think about no preservations from 100 years ago? 1000? 2000?
We could certainly continue to live and evolve and make the same mistakes again without such history. But it gives us historic context, fills our curiosity, and allows us to analyze long term developments.
Video games are a cultural good. Like music. Music was, is, and remains part of our culture. It enriches us. It's useful for entertainment, for creativity, for curiosity, and to share culture and interests with one another.
I imagine preservation fulfills our innate desire to collect and preserve what we gained. Loss of what we find meaningful or influential sparks negative emotions.