No, not entirely. They still need fuel for cooking and heating. Land and implements for growing their own food. In this day and age, we are all pretty dependent creatures. Could you imagine what this country would become if all petroleum products disappeared tomorrow?
The church owns all the land, and the land is chosen wisely. They have wood for heat and cooking. They grow their own.
They have their non-gas/nonelectric farm equipment, and can use their horses to pull it. They breed their own horses.
They're no part of this evil world. They've done everything possible to avoid what's happening to us (the "English"). They're slaves to no one. In fact, they're exempt from obomacare, too, because of their faith.