Is there something about a tenure of that duration which precludes someone from underperformance? Lots of middling engineers in the 15-20 year range are likely

Is there something about a tenure of that duration which precludes someone from underperformance? Lots of middling engineers in the 15-20 year range are likely to be coasting and over-compensated relative to their output. But those with a longer tenure did get a more generous severance package (more than a year's salary for a 20 year Googler), so they weren't treated with disrespect. They now have an entire year to figure out what to do next --- although someone who was there for Google's IPO is likely to be in a position to retire if they so choose.