You think you prove the theory? Really?
I'd like to disprove this theory - a friend of mine graduated from Uni and started a job as a Consultant at a multinational IT services company as his first job out of Uni. He earns twice what you do, and is your age. He would not have got the job without his degree, it was a prerequisite.
Sorry but earning £20k a year after 8 years of work does not 'proove' that a degree is 'not neccessary'.
What you really mean is that if you want to do helpdesk work and progress up from there, a degree is not required. Which is true - but if your aspirations after years of work are helpdesk then going to Uni isn't the best idea anyway.
The bottom line is that for some areas of IT, a degree is important. For others, it's less important and for some, it makes no difference. The earnings tend to reflect this, mind.
Experience is important but isn't the be all and end all - there are numerous people who are not really that good at what they do despite having done it for many years. Experience counts for nothing without the ability to learn from it and use it to further yourself. Heck I've got a decade of experience at playing FPS games on PC and Im *still* rubbish at them
I'd like to counter that knowledge is more important than experience on its own, but concede that experience is an excellent wait to gain knowledge