One could argue the chaos and uncertainty from upending his currently functional administration is not worth the upsides, while allowing for a natural transition via the standard election and end of term process is worth it.

He's just probably unfit to serve four more years, and for sure was too unlikely to beat Trump

See you don't understand, he IS fit to serve, but he doesn't believe he'll win the election.

The important consideration is that he’s unfit to serve for four and a half more years, and also that he’s unfit to win the election. In contrast, he’s probably not considerably more unfit for the next six months than for the past six.

He's unfit to serve another 4 year term. That doesn't mean he's unfit to serve the rest of his current term.

He’s mildly unfit to serve now but there’s reasonable doubt he’ll be at all fit in a few years. That would be what the more rational people should be thinking. It’s not about day one it’s about year two, etc.

Unfit to run a campaign, travel like mad, and get over an illness. An extended lame duck session now.

Time to wield the pen.