Thought provoking post, Escapeplan.
I agree there's wisdom in the tried and true methods and there definitely is ageless wisdom out there. Many people using IM fail to take any action and therefore don't put enough energy into manifesting what they want. There's got to be a giving/receiving dynamic here, paying currency to achieve a vision so to speak.
From personal experience, I basically see IM as a great way to open new possibilities which you may not have otherwise considered. It also makes the ride a lot smoother. But you still have to drive.
Say you want to make lots of money and you don't know IM... you suddenly have a billion different paths in front of you which lead you to that goal and some of them are dead ends. You could use logic to try and determine the best path, but it's so hit or miss. Watch any episode of Dragon's Den to see how many epic fails there are out there.
If you use IM, sending out the intent that you want loads of money, you would most likely get feedback in the form of synchros to start a particular business or get a particular job. This allows you to quickly choose the best path infront of you to get to the end goal.
It's so important to be able to be open to receiving these intuitions. I think that's where many people go wrong. They say... I want to make £1M in 2 years. And they visualize having it etc. And they just keep on doing that expecting it to fall on their lap sometime, when all around them there's probably signs showing them how to achieve it, but they're not open to seeing that.