How much have they saved now? Probably not much, and probably spent more.
It costs money to find the location, arrange the contracts, hire new people/lay off or move staff, and move equipment between rooms. Even then, many organizations may say it's cheaper to buy new hardware than it is to move 5+ year old servers.
However, the efficiency once many of those data centers is closed will become apparent. Space/power/cooling/networking/staff isn't cheap. Consolidating will give you some amazing savings a few years in.