I'm in the completely opposite camp. Many small files are easier to maintain with large teams. The one caveat is the files need to be very well organized. I'm personally a fan of having a folder for each component with separate js/html/css/test files living side by side.

In general, mixing html/js/css in a single file feels really dirty to me, but that might just be PTSD from a past life where I did a bunch of work on PHP spaghetti code with no separation of concerns.