I think people are looking too much at those who could have been chosen instead of Francis back in 2013. No one in their late 70s is likely to be elected pope next time around, and certainly no one 80 or older at the time of the election, which rules out a large portion of the names being discussed.
Assuming the next papal election is still likely somewhere between 5 and 15 years away, you should be looking at younger cardinals, or even in some cases those who are not yet cardinals at all, for papabile. No one currently older than 70.
Like we hear so much about how Biden is too old, but he's 6 years younger than Francis, who people are expecting to be around more than four more years.
This doesn't contradict what I said. 77 and 78
5+ years from now means at the latest early 70s now, or late 60s if you think Francis might be around for close to a decade. And they were both unusually old for newly elected popes, not by a huge margin, but fairly so.
Sure, if you expect Francis to keel over this year, bet on candidates who are over 75. But not if you think he has a fair amount of time left. And while certainly illness could fell someone in their late 80s at any time, Francis is quite spry overall with no obvious health problems, and the life expectancy of an 87-year-old man is still 92 on average (in the US, but that's pretty generalizable), higher if you are in overall good health and higher still if you have access to unlimited top quality healthcare, as Francis does.
