Yep, I don't think you need to be a commercial expert to understand it all comes down to contract management.
Whats in the specification? Now it's no secret boro insist on some pretty unique, bespoke conditions. Primarily that they can only sell the shirts in the club shop. It's a clause that is designed to ensure the highest margin possible for the club. Fair enough.
But you'd imagine it must have knock on consequences. If it benefits the club, the supplier then is going to lose out surely? Can't imagine it puts us at the top of the queue for reorders.
It also presumably impacts on the unit cost as the supplier needs to make money on the shirts too. If they're not making as much from the sales, you'd think they'd be charging more to the retailer. Or cutting down on production costs/quality. Or both.
And given the club shop appears to prioritise margin over everything else, I dont think it's a shock we end up with low quality products, regardless of manufacturer.
Adidas being the best quality, but probably because they were just taking a template shirt and sticking a badge on it.