This is an interesting point. For sites like Reddit, inflation is just a (minor) drawback because it means total vote count is a measure of (quality * recency)

This is an interesting point. For sites like Reddit, inflation is just a (minor) drawback because it means total vote count is a measure of (quality * recency) instead of quality. But for SO, where voting is never locked and content 'ages' at different rates, it's not so clear there's a downside. The "closed as duplicate" issue still stands, but rising user count is probably helping the problem.