The 'old school' of sales techniques generally comes from books that were bestsellers in the 70s, 80s, and the first half of the 90s. We've all read these books. So have our prospects.
Think about it ... over 80% of executives and decision makers were promoted up from the sales ranks. They were all salespeople in the 80s and early 90s when those books were #1 and everyone was reading them! As a result, they know all the tricks and techniques in those books (especially the notorious 'closes' such as the Alternate Close, the Ben Franklin Close, and all the other sleazy ones).
That's why the old stuff doesn't work anymore ... your prospects used to use the old stuff themselves, they know when you're trying to use it on them, and they don't like it!