Apparently that rabbit hole goes super deep in which the large auto manufacturers in the US throw their weight around and force suppliers into selling parts at cost or with razor thin profit margins. And on top of that, they force the suppliers to eat the loss when it comes to cyclical business demand (e.g. storage costs for over-producing during low demand and increased labor costs during times to under producing from high demand)
On paper Mexico reaped enormous gains from NAFTA(/MCA) but those went to a small slice of the population, and people on fixed incomes/not in manufacturing/services objectively got worse due to inflation and rising cost-of-living, property prices. The share of GDP effectively lost due to corruption is also an issue.
Ultimately it's a price control strategy to pit these suppliers against each other to lower costs. But it means that designing these electronic sub-systems isn't just a question of the design itself, but also of managing all of these supplier relationships as well, they all have different contracts, you would have to coordinate all of them at once to make sure things are interoperable, etc.