The selection process is via an election of cardinals. Generally, if a small group elects someone for a position, that person usually comes from that voting group. Therefore, while not a requirement, an elected pope is generally a cardinal.

Beyond that, a pope has great influence over the Catholic Church. It would be very remarkable that a young person could have that much influence over the cardinals to get elected. It could happen, but the likelihood is rare.

Because only cardinals can be pope and it takes a long time to work your way up through the priesthood into administration and such like any organization. Also, unlike most businesses or governments they never hire some young(-ish) new ceo or department head from outside.

The short, easy answer: it typically takes a lifetime of service for the rest of the church to determine if they fit the bill to be Pope.

The older the average pope, the shorter the average term, and the more papal elections in a given span of time.

One of the main powers of cardinals is electing the pope, so more papal elections means more power for the college of cardinals.

1. Because you can see his previous work and determine if you think he is suitable for the job.

2. If you make a bad pick he will see himself out soon enough anyway.

Pun intended.

Technically, they don’t have to be. They could elect a venerable whippersnapper cardinal - Dan Brown wrote a book about that. And that tells you how likely that is if he wrote the story. But it is possible.

It would be rare because it takes seniority to get into the position. And politics to be well liked enough to be put forward and then elected. By mostly old people. Some of whom would like the job themselves.

They serve for life (or until resignation), so if someone relatively young is elected pope, the same person will be pope for many decades. The cardinals don’t typically want that to happen, so they’ll tend to want to elect someone who is probably going to die soon.

What do you call old? John Paul II was 58 (? - I can’t find the exact dates he took power so I might be off by a year depending on birthday) which is relatively young. He then remained in power for 27 years (again because I can’t find exact days I might be off by a year). Which as others have pointed out is a problem: that was 27 years where anyone (read cardinal) who didn’t like the current direction had no ability to do anything. IIRC the previous popes before him only served a few years and so there was concern that they hadn’t served long enough to be useful leaders and at the time someone who would be around longer was desired.

Of course if you are 20 58 seems really old. However when you get older it no longer seems old. With average lifespans of about 80, at 60 you still have 20 more years. OTOH, starting about 65 deaths from natural causes start taking off (younger than that death is nearly always an accident) . How do you want to define old?

Im not sure if its exactly a requirement but priests have to have a degree and usually an advanced degree. Granted many get it in divinity but they also have to do seminary which can’t start until age 25 and it is at least 5 years. So priests basically start out at age 30 and technically a pope could make one a cardinal right away in practice the average age of a cardinal is like 70. Popes can be drawn from anyone but are usually biships. Bishop are required to have a doctorate in divinity and be over age 35. They are also expected to be known for all sorts of good qualities. So figure to be known enough you can add 10 years being a biship. So for all practical purposes its very doubtful someone would be name pope before age 50 and they have usually been 60’s or 70’s.

Gotta make sure they’ve had time to put together enough blackmail material on a candidate first. That way if he (c’mon, like it’ll be anything other than a “he” within our lifetimes) turns out to be too much of a reformer, they can shut that shit down.

Because Gerontocracy is the true law of the land, and is older than both capitalism and feudalism.