You don't think access to Biden is closely guarded?

OMG, no! Look, just yesterday he met yesterday with the entire team of the NHL champion club, in front of the press:

apnews.com - Vegas golden knights white house biden

If someone is genuinely non compos mentis, you can't have events like that. It doesn't matter how scripted they are. If he's literally incapable of making his own decisions, you can't hide that in events with a hundred or more participants, cameras rolling from every angle, over and over again. It will get found out. There's no way to hide it. You just can't do those kinds of things in large, mixed groups that will certainly - just by chance - include at least some people who aren't supporters of the President. If he genuinely was impaired, you just can't risk him doing something on-camera in front of a mixed group that inarguably demonstrates mental incapacity.

You certainly can't schedule a summit meeting with the Chinese President if he's non compos mentis, either. Because again, there's no way to conceal that in a one-on-one discussion like that.

They were not successful in concealing Wilson's debilitation for more than a couple of months, even while keeping him hidden away from everyone other than his closest advisors. In an era before video, before cell phones. It's utterly impossible for Biden to be non compos mentis and for it to be concealed.