At least one, if not two, entire generations of US Catholics gave up on even attempting catechesis. And, of course, the sex abuse scandals have been disastrous.
On a lesser note, Catholicism is a very rationalist and philosophical faith by Christian standards, which is not something which is as appreciated in the United States these days. It's not surprising that the biggest gainers among Christians have been highly emotion-based groups like Pentecostals. There is a real, albeit shallow, power to their approach.
Is it really though? Believing in transubstantiation would seem to require a suspension of disbelief and denial of basic human reason. I've always been puzzled by the fact that (some) Protestants take the metaphorical side on the Eucharist while Catholics believe it literally, when usually it's the Protestants who are the biblical fundamentalists.
