I bowled a tournament last weekend on a relatively flat, low scoring (cut was -9, strong field) 42' pattern that was pretty oily. The gutter was in play if you threw it well so there were some players using urethane off the gutter. I didn't notice the lanes transitioning much in qualifying but after a re-oil for match play, I followed someone who used urethane the previous match for 2 games and that pair was so much tighter down lane than anything I had seen all day that it made a huge difference in my ball reaction.
With that said, if someone wants to throw urethane, more power to them, you just need to adapt to what is in front of you, it just changes what the challenge is.
I do find it boring to watch telecasts where they all throw urethane though so from a popularity perspective, I think urethane is bad for the tour.