Pricing is both-and, not either-or. Money supply is definitely a factor, more supply, higher prices. The fed actions were just tapping the brake while fiscal policy created money out of nothing (see inflation). Prices are also subject to the demand side. When people decided they wanted trucks as daily drivers (especially in situations where it was more status/ego driven than utilitarian need, prices went up on trucks. (Demand-push inflation) Costs also drive prices. Companies are not going to sell at a loss (at least not for long). There are lots of other layers involved here including CAFE standards, alternative goods and profit margin. Every 'for-profit' corporation is legally obligated to maximize returns for its stockholders.
So, hypothetically, if Ford 'sets' prices they start with a bare minimum ROI they can expect. Just for fun, call it 10%. If they cut costs per vehicle by $1000 a vehicle, they could reduce prices by about that much and still make their target ROI. If demand is up, they can still sell for the original price and increase ROI. It would be fiscally irresponsible and likely illegal for them to price below market prices. They also have finite capacity in the short-run, which artificially caps supply at X. Sure, supply and demand set the top end price, but costs go up drives the denominator. The company must do whatever it can to keep costs in line. This is especially true in a competitive market. Ford has competition and people who do not like the higher prices will buy from someone else (or used, of defer buying, etc.) If the UAW got their way, prices of the 'big 3' would go up so far that Nissan, Toyota, Honda, Tesla, etc. would take additional market share based on price. The only option the OEMs would have is to cut costs...close plants, automate, move to RTW states or overseas.