I disagree with your assessment. We have five cats, four of which have been declawed. The three youngest were declawed somehwere between 8 and 12 weeks. They suffered no pain whatsoever. They were romping around playing rough with each other an hour after the procedure. Their mother, who was between 9 months to a year old, was declawed at the same time. She did have more pain and discomfort, you could clearly see her walking gingerly for a week.
The declawed cats still catch mice and gophers, climb trees and beat the snot out of our neighbor’s clawed cats. That might be because they’re between 18 and 20 pounds—they’re BIG cats.
Our oldest cat still has his claws, we use “Soft Paws”, which are vinyl caps we glue over his trimmed claws. Those need to be replaced periodically, so we still find scratches on our leather furniture.
Cats primary defense is climbing and that ability is impaired by declawing. Next defense is too grip the adversary with front claws while ripping them with back claws. With no front claws they cannot grip.
The lifespan of a declawed cat is roughly half that of one not declawed if cat is allowed outside.