Yeah this is one of the QoL things that you don't notice until someone points it out, especially as the SysAdmin. It's literally the first thing I do when opening a project: hit the collapse button. This lets me open only what I need to deal with and focus on it.
I see both sides, many may want it to default all-open like it does now. So make it a user preference. Also make it a global-settable default when most people want it that way (over-ridable by a personal default, of course).
