The reason that didn't happen was because most of the domestic electricity supply was US standard 110V, allegedly. The cost of conversion to 230/240v failed the cost benefit analysis.
Most USAF-occupied bases are dual-voltage with outlets for both 110 and 220. The 110 system running on internal transformer to the building, so there is no "conversion" - simply disconnect the transformer and leave the 110 outlets unused. Alternatively, you can run virtually all computer equipment and many other electronics on 110 saving your 220 outlets for UK-spec equipment. There's not much to it, really.