It seems to me that at some point, a critical mass of folks could leave, making it all but impossible for the remaining "church" to do much about it.
It's easy to sue and legally pick on one, two, three congregations, but if the Episcopal church has dozens of parishes leaving across the country, it will get exceedingly expensive to sue each one of them.
This has all been carefully planned, here, and in England, too. It will come to a head by February. The mill grinds slowly but exceedingly fine, etc. etc.