In terms of the specifics of trading methodologies, I wholeheartedly agree... in any case, I am one of those who strongly believes that the best trading methodology that you can have is one that you have arrived at through a blend of experience, trial and error, and the occasional bits 'n bobs of others... simply taking another guys methodology in its original form and trading it can't work in my view (unless the methodology is 100% systems based and the trader has a 100% systems trading mindset coupled with 100% faith in the vendor's system), cos I believe methodology needs to be aligned with the psychology of a given trader... and only a given trader can create such an alignment (usually subconsciously, as opposed to explicitly)...
Having said all of this, what some of the Market Wizards have done for me is to provide the occasional inkling or hint of information that I have interpreted in my own way, developed in a proprietary manner and incorporated into my trading strategies as one of my bells 'n whistles...
And, of course, another thing that Schwager's books have done, at least for me, is to inspire... take the example of a former meat-packer like Tom Baldwin who started out with a small grubstake of $25k and made a million in his first year, never looked back and became the biggest pit trader around... never underestimate the power of inspiration, since inspiration takes motivation for success to new levels... lest we forget that trading is simply an exercise in psychology (with perhaps the exception of the 100% systems traders)...
Then Gary emailed him again to say in a nice way that he didn't believe him. But Mark is still sticking to his story. 