No, but this is a market economy not a planned economy and airlines fly routes that make money. LHR-JFK/EWR is profitable due to high loads down the pointy end which cross susidises good deals down the back. To make sure you fill the pointy end you need frequency not capacity.
There's a reason why BA don't fly A380s to New York but all the other BA/AA/UA/VS/DL/KU flights are on wide body aircraft as Dave has said.