Origins of UK/US difference in pronunciation "herb"

The difference between AmE and BrE pronunciation of herb is probably due to the American tendency to retain the original pronunciation or foreign terms (in this case a French one) vs the BrE tendency to pronounce them according to the English spelling-pronunciation rules, according to the following extract.

You say ‘erb (using the silent French ‘h’), I say herb (the way it’s spelt). Here’s a good example of the difference between the American pronunciation (usually referred to as General American, or GA) and the Received Pronunciation (British English, RP) of foreign loan words — ie. words that have been adopted into standard English from other languages, many from centuries ago. Many will argue that RP has tended more to assimilate these words and pronounce them according to English spelling-pronunciation rules rather than to the way the original word sounds.

(www.glossophilia.org)