they were also very wealthy...thats what happens to mere resource economies.
There is a secret imho that spanish catholics used to know. It was the arian bishops in spain that invited the moors to cross from morocco to help the arian bishops against the trinitarian bishops. why? because all of north africa practiced arian christianity. They just rolled over for the moslems. (in much the same way as europe does today.)
600 years later when the catholics put the Abegensians of southern france to the sword — it was because of the existential threat that the Abegensians posed to Christendom. Why> because the Abegensians were also Arians.
John Calvin put the founder of the Unitarian Church —Servitus to death. Why? He was also an Arian Christian. I would bet that Calvin had access to Catholic archives on the subject—which was why the punishment was so severe.