If people live indefinitely then I would have thought many short term thinking issues would disappear: people will directly care about the future of the planet/environment/global warming.
Wealth accumulation is an issue, but this also is an issue with family dynastic wealth. Law and tax mitigate that somewhat and a similar answer could be used for this also.
It may be that some of the Conservatism of age is attenuated in a society of constant youth.
Overall I think it may be a positive on society, and the costs can be mitigated somewhat.
>people will directly care about the future of the planet/environment/global warming
I don't think that's a given. Many people flat out don't believe in human-caused global warming, at least in America. A lot of people would also interpret it as an act of God-- perhaps judgement day coming- over the scientific consensus. Of course some people also hate to take responsibility, and we all know at least one person who avoids taking responsibility of their own life to the point of ruin.
I don't think society as a whole thinks as similarly as many assume they would. I also don't think humans are as rational with their decision making as we think. Once people acquire habits and addictions, they themselves have a hard time leaving them. I don't believe humans were designed to live forever,and all too common selfishness and ignorance proves that
