"are not as effective as everyone sharing the same physical workspace. Yes, they do help mitigate many issues of isolation and they do help collaboration but there's still some "bandwidth loss" when people are not in the same room or even down the hall from each other."

Agree. Which, in fact, was one of the reasons that both Bell Labs and the Manhattan Project achieved what they did. (For sure a different time which lacked many of the advantages we have today.) And you could also argue about the negatives, the distractions etc. [1] But there is no question that in many cases it's an advantage to be located near others working in the same area and not in near isolation.

[1] If you don't like listening to music (I don't) use a set of 3M "tarmac" grade earmuffs which will block out nearly everything.