Gothic cathedrals don't take centuries to build - the Hagia Sophia in Constantinople was finished in a mere 4 years, which will substantially change the look of many of them from what we are used to - you won't have many of them left unfinished nor would you see the evolution of the gothic style in one structure with e.g. different south and north towers, a high gothic choir and a flamboyant gothic nave etc..
Especially the framework of gothic church windows and the highly decorated spires would have been significantly faster to produce if they could have been cast in concrete instead of the slow and arduous artisanal masonary production of OTL.