1) economic: the farm based community where families could produce their own livelihoods has been on the way out for a long time. It seems difficult for a good sized population of Catholics to be trained to live in a traditional agrarian manner. Only 100 years ago such communities comprised a significant proportion of Catholics in this country.
2) cultural: the wider culture is now thoroughly pagan and its values are constantly bombarding people, young and old, electronically. If any significant fraction of the children come under the influence of these things they will corrupt the others.
3) lack of zeal: this is the main problem. The early Christians did not compromise with the pagan world they lived in. A community of people who long continually after the onions and leeks of Egypt will never be able to survive
4) ignorance: as the years from Vatican II increase in number, the percentage of people who have any concept of what a traditional Catholic community should be like, as well as the number who even really have an accurate sense of the religion and its teachings continues to decline. I believe by the time my parents generation has passed away, the last generation raised before Vatican II, "Catholicism" will become unrecognizable as something in continuation with the past for most Catholics. The insanity of fisheaters posters and the insanity of liberals who are really just upset about abortion and ɧoɱosɛҳųαƖity and not about other problems in society is unrecognizable as Catholicism.
5) Cult mentality: both clergy and wealthy benefactors would have to put aside egotism and based their actions fundamentally on charity and self-sacrifice. They would really have to want what is best for everyone, and truly want to have a Catholic culture, as opposed to embracing bourgeois or obscurantist values, as we see among neotraditionalists.
Overcoming all these problems would be a very tall order - in some respects it might be nearly impossible.
As Bishop Williamson has said, the family and home must be fortified.
If a person can maintain his family in a rural area in proximity to like minded people, that is the place to be.
More stringent values are needed. The values of the past were far too lax. And that is why the collapse took place. There never could have been a Vatican II if most practicing Catholics hadn't already compromised fundamental beliefs. The liberalization of the SSPX is precipitating a collapse in serious practice among younger trads.