Should Biden drop out based on his debate performance?  I don't know. Answering that sensibly requires two things that are not currently publicly known:

- The actual state of Biden's health, with an informed prognosis.

- If he's fit (see above, I don't know), the political landscape, based on highly granular polling data and informed analysis.

I'm neither an MD nor a political analyst, and I've neither examined Biden nor have access to the kinds of political data that campaigns use. 

 But are you a competent human with eyes and ears because he’s clearly suffering from dementia.