I'm not old (only 60) but don't think that's the case, quite the opposite as skin gets looser in older people. And who said anything about lack of use? With all the stresses of the ratrace behind them, the healthy elderly have more time for leisurely pursuits.
The other issue that I didn't see among the various speculations as to what the original grounds were for circumcision is the question of scent. The smegma is not just a lubricant, it sends out a pheromone signal that triggers a sexual attraction response in a woman who is within sniffing distance or even further. This isn't a big problem in a matriarchal society but in a patriarchal monotheistic society where a woman or women are the chattels of a man this is totally unacceptable. Total lifetime loyalty is the deal and the upkeep of the offspring is the accepted responsibility of the male. So removing the scent glands of all eligible males by circumcision is the most effective way of ensuring that some opportunistic 'coveter of his neighbour's property' doesn't smear a bit of smegma down at the village well and then sit back and wait for the furtive housewives to turn up once hubbie is snoring away at home.