One reason I've pinpointed easyJet as a possible pathfinder to sort out this industry-wide idiocy is because they are big enough to take control of their airports, yet not so big as to make a change impossible.
I imagine that they can do pretty much what they like at all their UK bases and therefore (for the UK traveller) the potential is there to "enhance the customer experience" on 50% of occasions. That's a very good start.
And they have a fair few European bases too, though (as mentioned above) somewhere like the current SFX is a basket case for understandable reasons. At the end of the day, it is all down to local staff. I never cease to be amazed at the inability of contracted handling agents to simply do what their airlines ask, even when there is an airline station manager in close proximity. And even locally recruited direct employees can often get it wrong.
Anyway, just sorting this out at the UK end would make a lot of people much happier. I don't know what's worse, the boredom and physical pain of queueing, or the feeling that one is being treated as a complete mug. Not nice either way.