Ok, so you're not talking about private channels here, just about the fact that we don't know how frequent channels are in use.

Looking at my node statistics at five-satoshi.com i can see a stable volume of transaction for a while now. Also the appearance of my node in shortest routing paths is quite stable.

This obviously doesn't tell anything about the usage of the main routes, but it shows that the offroad routes aren't used more. Which leads me to the conclusion that the main actors are setup with sufficient channels between each other.