Hi Graham
I think you just identified your own niche:
after all that time studying the "gurus" and still not making a cent, you probably have enough stories for a website to debunk all the gurus' theories, and to warn other people not to waste their time with yet anoyther get rich quick scheme.
For example: does anybody else think a particular guru is actually a guru, or is this belief confined to the guru him/herself?
Is the guru making any money from his own theory or just from flogging it?
The internet is just like the real world I think: only with a brilliant idea and a lot of work you might get somewhere.
Too many people think they only have to spend $29.95 for some six emails and they will be buying a Porsche.
Do what you know and do it well!

Cheers