Most of those CO's are in buildings that don't have all that much space in them, were built in the 40's and 50's, and likely aren't suitable for that kind of thing. Cooling would be a big deal.

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.