There are other reasons for longer lifespans, but you’re implicitly saying all of them combined are not enough to counter the reasons you give.

Now, I’m not certain either way about the broader social impacts — I personally very much want to live longer, and yet I am also aware that my personal interests are not always aligned with group interests, e.g. tragedy of commons, Nash equilibrium, prisoners’ dilemma — but it is extremely unlikely that any negative consequences are perfectly balanced to positives either personally or collectively, so I am absolutely certain that the one thing we should not do is leave lifespan as is.