Bowler,
I think I get your point.
Expensive, marble laden churches can give the image of religion without the substance.
Here are two different examples:
1. In the 1990s, a Chinese friend and I went to see St. Joseph's Cathedral in San Jose, CA. It had just undergone a $20mil restoration and the interior and artwork were exquisite, despite the fact it was a new mass design.
My Chinese friend was so overwhelmed by the restoration job, he stated he wanted to start going there for Sunday Mass.
I think he was impressed with the material grandeur and wanted to take his girlfriend to a classy church. However, religious doctirine and worship of God were not of his interest. This could be one example of your point.
2. In Covington, KY, there is a most beautiful Cathedral named St. Mary's of the Assumption Basilica built in 1895 and elevated to a Basilica by St. Pope Pius X.
If you walk through the surrounding neighborhood of this parish, you'll see mostly modest and humble homes.
It's obvious the faithful there funded this church, with a large portion of their hard earned dollars, for the honor and glory of God.