a discovery like that is not going to be kept a secret, it's too big of a breakthrough to be kept a secret. So you can bet that all the people who dont have it, will demand it as well.
I don't think there will ever be a magic pill that suddenly changes the 90 year old into a 20 year old. When people find out the "secret" to living forever is what you were told all along, nobody's going to be demanding anything, for instance:
-You keep thin to minimize stress on your joints, vascular system and organs
-You exercise for two hours every day to keep your heart and skeletomuscular system strong
-You never smoke
-You get corneal transplants to replace cataracts
-You use moisturizing sunscreen every day and keep yourself covered in the sun.
-You read and learn every day to keep your mind strong
-You drink no more than 1 ounce of red wine per week (and no other alcohol) to minimize stress on body and likelihood of gout and other diseases
When people find the burden for long life falls on their OWN efforts, and they can't demand or steal a magic pill, they suddenly lose interest.