The point is that if you try to prevent pricing of goods, you get a) pricing by other means, often more inflexible, b) underinvestment and underproduction, c) departure of the wealthy through other markets.

The problem with road pricing is usually not the pricing per se, but rather, that the government bodies doing the pricing just apply the revenues to something totally unrelated, breaking the connection between services and revenue. Road pricing can work if it is actually used for maintaining and building the road network - a genuine pay-for-service model.