Isn't it true that most people shoot prone better than sitting, and about as good as from a bipod?
Prone with a sling is more stable than sitting or standing with a sling.
Bipods changed the Long Range F class shooter targets. Originally they were using the same 2 MOA target as the sling shooters. But shooting off a bipod and bags is far more stable than sling shooting. So now F Class used a 1/2 MOA target and yet, even with that tiny target, the current F Class National Record is 200-17X , if that has not been broken yet.