I've noticed a pattern: the people who call the most loudly for the Catholic Church to give up her art, or churches, or other worldly possessions tend to live pretty cushy lifestyles themselves. The most beautiful Catholic churches in the US were built with the money and hard work of poor and working class immigrants. I always laugh when people blather on about the supposed wealth of the Catholic Church since anyone who's ever been involved in the life of the Church can tell you that many parishes have trouble paying their light bills. Harvard University's budget is ten times greater than the Vatican's.
If you don't believe in God or if you don't believe the Catholic Church is the one true Church of Jesus Christ, then you probably see the Church's supposed wealth as swindled from gullible peasants. Remember Scripture when Judas rebuked the woman for pouring expensive oil over Jesus. Jesus said that the woman had done a good thing and told Judas to leave her alone. Judas got on her case not because he truly cared about the poor but because he was a thief. Likewise, it's rich to hear people claim they want to hold the Church to a higher standard when they themselves do not believe in the higher standard. For Catholics, Christ IS the standard. Plato asked if a thing was good because God commanded it or if God commanded it because it was good. If it's the former, then morality becomes arbitrary. If the latter, then God answers to a standard higher than himself. The solution is that God IS goodness. What standard are atheists and pagans using when they condemn the Church?
The Church doesn't build beautiful ornate churches for the glory of man. She builds them for the glory of God. Doesn't God deserve the best we can give him? Obviously not every church can afford to make itself as splendiforous as St. John Lateran, but God doesn't expect that much from everyone. The widow's mite was more meritorious in his eyes than that which was given from surplus.