Be careful what you wish for.

Hot reloads can become very expensive. Especially when it comes to computationally heavy tasks that notebooks are built for.

If you decide you want hot reloads by default, it'd mean each time you click on a cell and then click on another you'd be restarting the whole notebook.

If you had massive datasets you were loading or other args that you were parsing manually or at prompt, you'd have to go back and do all that. Don't even get me started on the operations you'd have done with those dataframes prior.

I think it is a good thing that notebooks separate instructions and re-execute manually by default. The cost of the alternative is just too high