It’s probably not that surprising by now.
I’ve never had a supplier tell me my designs were easy to make. I think it’s like that old phrase, “This would be a great job, if not for the clients”.
Most products are difficult to make until you nail the engineering and processing. Particularly as devices get smaller and smaller and you’re trying to assemble products that have almost nothing in the way of screws, just snap fits and adhesives.
I take it as a sign of laziness when the engineering team refuses to contemplate ideas that are even remotely outside the parameters of exactly what they have always done in the past. “We’ll have to spend a day adjusting the __________ - we can’t pursue anything that changes that.” They you spend three weeks problem solving around the sometimes value-subtracting limitations this creates.