Web designers who went off to photograph Alaska would be battling evil demons and taking the photos as a cover story for why they were there. And so on. Also, not everyone who is top-notch in a field is necessarily famous or swamped with obligations. It's entirely possible to be a fine violinist but to be almost entirely unrecognized outside of a small circle. This both is and is not true.
Some abilities do require a lot of maintenance.
Others take decades to come to the same level, and require more practice. If you're an exceptional doctor and you're two years out of your medical practice you probably haven't lost but a tiny fraction of your knowledge and ability. If you got back into practice and read a couple of journals to bring you back up to speed, you might well be back up to your old level, especially if you have a quick mind. Yes, it's ridiculous to say that you haven't practiced medicine or picked up a medical journal in fifteen years, but you can still doctor with the best of them the moment you're called upon. But it's just as ridiculous to say that after two weeks, you've forgotten how to hit a bulls-eye in target practice.