Earlier quoted context omitted.
So we have a measure that is, at best, “marginally effective” as a theft deterrent by your phrasing and actively harms consumers while actively benefitting the entities that artificially impose it. The only theft it is preventing is other carriers stealing customers from one another.
You seem to think marginal == zero. Which is the part that is confusing me.
I am arguing that the reduction in theft due to carrier locks is 0. You are arguing that it is small (marginal).
I am saying that no matter what, the actual cost of the carrier lock to the consumer (as demonstrated by used phone values on eBay), is far higher than whatever marginal benefit you are arguing for.
It is a massive net loss to the consumer, and the only guaranteed beneficiary is the wireless carrier.