I disagree, at a certain point the price is too low. The F-body was killed because GM was losing money on every one of them. The price was already too low and they weren't exactly flying off the lots. However, paying $10/hr to bolt in the seats instead of $40/hr would have helped the cost and might have saved the F-body.
Price is a reflection of not just what the market will hold, but also what the product costs in the first place. What GM needed to do was cut costs so that those two numbers would come into line.
Replacing overpaid workers for ones at a reasonable pay rate is a huge step towards making the company profitable. Unfortunately, they can't do that with the unions around or they'll be tied up in the courts with wrongful termination suits until the next ice age. You're right that Unions aren't the only problem, but they are a big one nonetheless.