Many of the people electing the pope have hopes of becoming pope one day themselves, so they elect someone they expect to outlive.

You should probably understand the priesthood is a career by election of mateship mainly. If you have a desire to rise through the ranks it’s basically about who you know vouching for you and it takes decades to get to the level you see at the Vatican where only a tiny minority ever make it.

A person in their 30s and 40s is only beginning this career. It would be like taking a warehouse worker at Amazon and making them CEO.

They don’t want them in there long enough to make any real changes

When John Paul was around people bitched about how long he was pope.

One more thing that hasn’t been mentioned - the pope is the figurehead of the church, and needs to look the part. Why does the pope have grey hair? Because people expect the pope to have grey hair. Stable symbolism is important in an institution like the church, as much for followers as leaders. Electing a pope who doesn’t “look the part” could cause defections and schisms.

Because he is elected for life so having long track record of things he has done is important to figure out if he is suitable for he job.

And if he turns out to be a bad pope he will see himself or soon enough. Pun intended.

Grey hair = too old to fuck children.

At least that’s their belief system not their reality.

It’s a passive cosmetic effect once you get to that level

You know how there’s a saying about banks,(I’m paraphrasing) “If you’re in debt $100k, the bank owns you. But if you’re in debt $1m, you own the bank”? Same way in church. If it’s one boy, or 100 boys.