yes, although the vast majority of circumcised individuals can still copulate, feel sexual gratification, orgasm, etc., the level of sensation loss is so massive that the two experiences are not comparable. As someone circumcised after their first sexual experience, I can confirm this fact. While yes, you can wear a cock ring to immobilize the foreskin to simulate the loss of gliding action, the sensations brought about from tissue that is removed in circumcision makes that simulation a still better experience than the circumcised experience.

All that said, the level of sensitivity declines as you age after circumcision because the head of the penis will generate a thick layer of keratin in response to external friction that wouldn’t occur if the penis was covered by foreskin, much like a callous that develops on your feet or hands from over-manipulation/exposure to stress. Many accounts of adult circumcision cases fail to follow up with patients as they age and the keratin layer develops over time.

My penis was incredibly sensitive feeling following circumcision, but some time later it was dull feeling. Years later, it was numb to sensations of temperature and light touch.

Now, that said, I’ve been undergoing circumcision reversal, and I’m about half way restored. The only parts that have improved are the keratin layer (gone now, temperature and light touch are restored slightly), and the gliding motion.

the feeling in the rigid band? Gone
the purse string muscular effect of gathering the skin forward? Gone. (Although skin tensing still occurs when I’m cold, it’s not sufficient to keep the skin forward, and the muscle is gone, so the skin doesn’t collect forward by itself)
the frenulum? Drastically reduced; in fact, the amount removed varies case to case because our individual anatomy has variation, and the procedure is done by humans which also introduces variation
the amount of mucosal derived lubrication? Drastically reduced