Thomas - the thing is that this isn't in any way general. It's particular.
Let me confess - when the idea was first mooted I was in favour. I like motorcyclists as a breed (despite their malodorousness, and their distinct lack of interest in couture), and, as I've said, I do use them as a training device. But - time and experience proved me wrong. The motorcyclists took to bus lanes like bats out of hell. They whizzed through the throngs of cyclists without a care in the world. It takes a fair bit to alarm stout fellows like AdrianC and yrs truly, but they did - and they terrified the less experienced - the love of my life included. In other words - they blew it.
I think cyclists have got to get over the shy and retiring bit. In a world running out of oil, and government expenditure on transport under the cosh, we are the dreamboats of mobility - the chosen ones, the shining lights of the world, God's anointed, the Salvation of Streets, the Ones Who Must Be Propitiated.........civilisation needs us to ride bikes, and we're due a whole shedload more consideration than we're getting at the moment. By contrast nobody actually needs motorcyclists. Which is tough, but, hey, that's the way it goes.........