Well on most...well some at least, airlines you can pay extra for priority boarding...I never bother but I assure you it is available....could be just the start...:-(
Last time I used a fast track, checking in, on EasyJet, my queue ended up longer than the regular one! One of the check in staff left about half way through and was not replaced. This was in France, the land of 'liberty, equality, and fratenity'. Maybe the staff thought there should be more equality and took a liberty. Didn't generate much fraternity though.
I paid extra on The London Eye to "jump the queue". The queue was about 2 1/2 hours wait and as we were only in London for the weekend and had other places to visit, it was worth it. Waited about 20 minutes.
I've mixed feelings about this, I suppose if you can afford it, it's worth it, but I do feel it might cause a social divide. Some airports and theme parks do it here already, I certainly don't agree with it for traffic, we all pay our road tax, end of.