You contradicted yourself. Many companies like McDonald's and Walmart promote from within. You can be successful at those companies by working hard and getting promotions.
Theoretically possible yes. But the pyramid is very very bottom heavy at McDonalds and Walmart where 90% of all employees make close to minimum wage. It would be better to start in corporate at Walmart and work your way up there, rather than to start as a restocker or cashier or warehouse worker -- all of which are at risk of being further automated.
> It would be better to start in corporate at Walmart