I have been in ~15 CO's - there is tons of floor space in them, and the only thing telephone switching equipment has done since the 50's is shrink - beyond that, most existing CO buildings had expansions when electronic switching came about, because they couldnt add the new electronic (1/1A/5 ESS) without additional floor space. Cooling is noted by the requirement for NEBS compliant equipment.

The older ones have lots of tall windows. It's the newer windowless ones that cannot be easily repurposed, unless you want to build a data center.

I want to know so badly what the telcos are still doing with all that space. Some, like mentioned above, are probably edge data centers. I imagine there's a lot of Internet infrastructure in them as well.

But even the biggest IXP is surely tiny compared to the space required for an electromechanical exchange (that would host human operators as well). Are there just floors and floors of empty space? Like you said, on very expensive downtown real estate?

it makes sense when you realise they are actually machines disguised as buildings