The city itself would be built differently.
Kenneth T Jackson mused that if New York remained the capital, it would be built focusing on political glory - a task easier to do after the fire of 1776 and the TLC of British occupation. Without that, it was free to focus on capitalism and evolve into the city we have today. So, New York would probably still be an alpha city, but it would likely be a very different one.
Modern London is both the political and economic capital of Britain; it remains the economic capital of Europe (for the next 2 years at least
Can anyone articulate well the ways in which being the political center of the Empire impeded rampant capitalism in London?