I'm very much looking forward to the longevity/healthspan movement succeeding: I there is an immense amount of good that will come from having healthy 150 year olds around, who still have the stamina to pound a fist on the table. I expect there will be a lot less ageism and their wisdom will be worth gold for businesses willing to listen.
It could be a problem in science and politics too. Science already has issues with new ideas being very strongly resisted until the generation in power flops over. In a world where people live healthily to 150 and beyond, the young would quickly become a permanent minority with little voice. Risk of stagnation would dramatically increase across all fronts.
Imagine someone of the calibre of Feynman at 150!