I know partially why this is happening. The parish I once attneded is in a very liberal area and was of course liberal. The small group of less liberal members struggled to remain but eventually many converted to Orthodoxy.
The nearest Orthodox church is made up of 1/3 former Catholics.
The unity of Rome breaks down at a practical level as noted in the article below. A family friend, once their kids were school age, converted to Orthodoxy so as to be able to send their kids to the Orthodox school (one has to be Orthodox). They didn't want to send their kids to the public schools and the Catholic schools are very progressive here. A forced conversion in a way but they are happy and have since brought some of their family members into the Orthodox church.
Attached is a great article on this. I'd love to see a show devoted to this topic as Rod Dreher raises some serious issues.