Data is Beautiful

a lot of those people are too old to work, let alone in a role that requires decades of training and experience to do competently

That's fundamentally a problem with democratic politics. The job of a politician is not to governor, but to campaign. The goal is to hit the magic combination of fundraising, friendly media, and popular approval to outpoll every other contender on election day.

A big advantage in campaigning is incumbency. Politicians get all of the above simply be being in office (which is why getting appointed a Senate seat by the governor is such a sweetheart deal).

Add to that, Senators serve for six years. And while I'd argue folks 60-70 years old are perfectly employable, you get into dangerous territory if you're winning a seat at age 76 and holding it into age 82.

If they plotted Senate representation against proportion of workforce, rather than population, the discrepancy would be even more glaring.

Maybe weighted against income. But there are a distressingly large number of senior citizens who still need to hold jobs in order to make ends meet.