If you didn't screw up parenthood, that isn't even remotely true. If on the other hand the only meaning of life is chasing the best, money, career or similar bullshit, then yes you probably end up feeling as failure at the end.

Yesterday there came folks from land mines removal agency, looking for donations. Imagine if you contributed to some kid not having legs blasted off / being killed for the crime of running few meters off the path. Imagine if it would be 100 kids. If that isn't fulfilling then I don't know what is.

Generally giving and helping is very fulfilling. Easier done if you have plenty of family/close friends, but not a necessity. Jordan Peterson claims fulfillment can be had from accepting great hard responsibilities, I tend to agree with him.

Those who give more than they receive definitely don't have these kind of concerns as they grow older.