"Long have I watched this one... Never his mind on where he was, what he was doing"
That is not exact, but that is Yoda talking about Luke on "meeting" him in ESB.
This is all speculatory, but seems sensible (oh god, don't tell GL)...
Luke was not trained early because he would have created a disturbance in the force perceptible by Palps and Vader at the point where he became a Padawan, and he would not have been nearly strong enough for the confrontation, despite the superior Jedi training he would have received - a kid is a kid, and a kid can't hang with the DLOTS. Obi and Yoda needed Luke to have some physical maturity, and perhaps be grounded a little more in the mundane, so that learning the ways of the Force would be done through a more mature (if still totally whiny, weak, weasily) way.
Yoda knew, from his 1 on 1 with Palps, that his days as the Force Master were behind him - that he could not beat Palps alone anymore. Obviously then, neither could Kenobi. So, they both went into hiding, waiting for Luke and Leia; trying to live long enough to pass on to them what they had learned and give the new generation a fighting chance.
This isn't really a revelation, is it? It is, I think, pretty much what the movies have told us.
I think you underestimate the power of Palpatine, and the power of Luke. (the latter I understand easier