Perhaps a small visual indicator that's proportional to upvotes would be helpful, but other than that, I too wouldn't collapse anything automatically.
The thing modern web UX trends forget is that human visual system is amazing at pattern-matching and filtering. It's literally what it does all the time - subconsciously sifting through large amounts of data and focusing on things of interest. As long as there are patterns in the data the brain can use to slice and dice it, you can dump a lot of data on people with no confusion or loss of effectiveness.
The thing modern web UX trends forget is that human visual system is amazing at pattern-matching and filtering. It's literally what it does all the time - subconsciously sifting through large amounts of data and focusing on things of interest. As long as there are patterns in the data the brain can use to slice and dice it, you can dump a lot of data on people with no confusion or loss of effectiveness.