1st: Public perception has zero impact on wages, or anything to do with this topic. Respected or not. supply and demand effect price. Strippers and hookers might be an example of an occupation with a low level of public respect, but when there is little supply, the price goes up. Too much supply, the price goes way down. Let's not discount quality in this analogy...
2nd: Too many drivers available with decreased demand certainly effects wages over time. "Competitive wage", becomes less relevant in such a market. We have seen this in the past, Red. FedEx has capitalized on such market conditions in the past, just like every company in the industry. Wages may not go down but they most certainly stall/stagnate, as do working conditions. Simply undeniable.