Question - why did America insist on building its Interstates directly through the centre of every major city it could think of?
It'd be like the M5 running up Queensway and the Aston Expressway.....
To be fair I I don't think it's just the USA, many countries have, it's simply that the USA is so much larger in terms of population/wealth and has been for so long that it is the prime example, while the UK sits probably at the more conservative end of the spectrum in regards to urban motorway building. South Africa followed the American example with urban freeways in all three of the largest metropolitan areas plus Port Elizabeth, though of course on a smaller scale. Many other countries did too.
They didn't just build them through/near the centres, in most cases American cities have outer bypass routes (sometimes multiple) as well as urban ones, to allow access to the city centres plus to allow long distance traffic to bypass them.
I wouldn't advocate wholesale bulldozing of historic districts for road developments, but in my opinion the attitude in Britain has swung to the sentimental extreme and of overvaluing architecture that is extremely common in the country and therefore blocking useful schemes.... often the attitude seems to be that some very common late 19th century buildings are worthy of the protection afforded to extremely rare historical gems.