While the decline is not universal, shrinking parishes is itself a reason to sell older and more ornate churches and either build smaller strip mall ones, or merging several parishes into big expo center ones.
Of course it only adds to the decline when the hierarchy builds as if going to Mass is no different from a trip to the mall or seeing a show.
There’s also the hypothesis that if the Church gets prestigious awards for their avant-garde architecture people will finally start liking the Church again.
What'd be funny is to take a bunch of teens who have never attended a church service and have them sit through the different denominations' services to get their reaction.
The only thing funnier than witnessing a Catholic mass while having no idea of what it's like beforehand is the idea that some people still fervently argue for the masses to be exclusively in Latin. Because if there's one thing better than medieval LARPing, it's medieval LARPing in a dead language.