When all the lower end chains can include Wifi in the room rate but the higher end chains cannot, that tells me it has nothing do with trying to recover the cost of installation.

It has everything to do with knowing that business travelers staying at the higher end hotels need Wifi and will expense it anyway.

I think we're slowly seeing hotels realize that Wifi these days is as basic as towels and pillows and should be included in the room rate. It'll take time, but it will eventually happen.