This is not a list of who's made the most money. That's a completely different argument, especially because the industry has changed so much in just the past 20 years in terms of what actors get paid. We want to know which actor or actress most consistently produced big hits the over the longest period of time.
Keep in mind that Tom Hanks hasn't even been a top ten draw for 25 years and you begin to see how difficult this list is to crack. Realistically, Harrison Ford can qualify, thanks to the success of the last Indiana Jones.