[i.h]

Sure, but there are various significant political and cultural reasons for that. With maybe a few exceptions, that isn't true for the patchwork of areas with very disparate population sizes that make up the BBC Local Radio network. Beyond petty rivalries, there isn't really much sociopolitical distinction between a lot of neighbouring Local Radio areas, creating arguably unnecessary duplication (even with increased simulcasting). 

While you might be sacrificing a degree of localness, a Regional Radio map that largely corresponds to the TV region map would not be losing much in terms of broader functionality - allowing for fewer, but better resourced stations with an overall lower pricetag. It would also allow for a noteworthy reduction in the BBC's property portfolio, a significant non-content related cost.

I don't think many in England would agree that it's one great big monolith, nor that things are suddenly drastically different once you cross the border into Scotland or Wales. Not enough to justify the already massive disparity in English local/regional output compared to the rest of the UK.

the BBC's "regional radio" plan only increases the disparity while putting it down the same path as the major commercial radio groups. If the BBC was going to embark on a plan to have fewer regions but with Scotland/Wales/NI style autonomy, that could potentially be welcomed, but clearly that's never happening.

It's certainly ridiculous to suggest that England should not have local radio because Scotland and Wales don't have it.