If GM’s business decreases by 50%, their 2,700 suppliers will also suffer. Let’s assume each of GM’s suppliers has ten suppliers and the supply chain ends there (it doesn’t) - that is 27,000 businesses who are negatively affected.

50%?????!!!!!!! In one year? thats beyond ridiculous, its econ science fiction. Like a 10% fall in revenue, and they'll be shitting themselves. Theyll pay for it with forced, unpaid vacation for ppl in the plants if it comes to that, not by dicking over their suppliers..