Almost every time I go to the big city it is empty of people. And actually, iirc, the ton would usually only spend the Season in London and go to their estates for the rest of the time.

I don't know the answers to everything. But I do know that generations have been getting more stupid and we have lost a great deal of skill.

Master craftsmanship would take a lifetime to learn and they would have been geniuses like Leonardo.

As we increased tech, we chose function over form.... and ended up with neither.

In some ways, I think this may be a psyop against Europeans, like we couldn't have built this.. well, we could have. If not us then who? Africa? Aliens/demons? Previous civilizations? It is entirely possible (and likely) that the French didn't build or invent anything, of course.

However, the architecture in the colonies was influenced/created by Great Britain. For example, they would have expert cartographers (skills now lost) make a map of the new land. They would send the info back to GB via ships. The British would then design entire towns. The design schematics would be sent back to the new world to be built.

William Shakespeare is known for being born and buried in Stratford-upon-Avon. So the British decided to create a theater town and call it Stratford in Canada.
Unfortunately, the design got switched with that of a different city on the way over (they had one job!) And the British on the ground built the wrong design. That is why the other city looks like a theater town instead. You will notice that in pretty much every British colony they have the same names for streets and cities.

Things can change rapidly. There used to be a country called Rhodesia that the British created and was destroyed.

On the other hand, if most info today is fake, probably most of history is too.