I've seen his name mentioned a couple of times for 2020 I also saw some rumors about him leading up to 2016. He would have instant 100% name recognition and be a fundraising juggernaut but he will be 72 and will not have been on a ballot in 20 years
If it has been so long since you've held office that there are people old enough to vote who have no recollection of you holding office, you don't have 100% instant name recognition.
There will be voters in 2020 who were not alive when Al Gore was vice president or ran for president.
It would be like if Walter Mondale ran for president in 2000.
