Collapsing Ticket History / Quoted Emails

I’m in the process of setting up RT at my company.
It’s the SOP for our support, and for our clients, to always reply to emails including the full email trail so that people know what you’re talking about. As we will be using RT almost exclusively by email, I expect the Ticket histories to become massive, and presumably take ages to load.

A while back there was a discussion about having a collapsable ticket history.

Did it ever get working in 3.6+ code? Is it now an official RT feature that can be turned on? (fingers crossed)
Did it reduce the load time of the ticket history? Did the history load in collapsed state first?

I can’t strip out quoted sections of emails in case they contain something valuable.