Past performance does not guarantee future results.
No, but hints that the longevity is not just luck, but an exceedingly sturdy rover.
It's twin, Spirit, died almost 10 years ago. It might still be alive too if it hadn't been trapped in the sand.. or it might not. Clearly we need to send more rovers to get more data points for statistical analysis.
Every day is a data point but I agree we need more rovers.