I believe your hypothesis is not entirely correct. 9 of the 10 tallest buildings in NYC are to be completed between 2000 and 2021.

https://en.wikipedia.org/wiki/List_of_tallest_buildings_in_N...

In Europe, if you exclude Russia from the top 20 tallest buildings, the UK (2), Germany (2) and Spain (2) have the tallest buildings, with the UK and Spain buildings built in the 2000s.

https://en.wikipedia.org/wiki/List_of_tallest_buildings_in_E...