I am in the same boat as you are. I never measured anything until we got a couple decent ones in 2012. I might have a few in the 160 class, but nothing I would be happy with today. I think it does take a long time before a person can be mentally tough enough to stay the course and pass on great looking bucks. I am spending the money this coming year to go hunt ID in November. I think I am just now getting to where I can truly dedicate myself to the big one.
tidbits:
We took those 2 big OR bucks(both about 160") at 1:00 in the afternoon. They were big mature bucks, just topped out at a good number instead of a great number. They were near other deer in the morning, but went an entirely different place at mid morning than the rest of the herd.
I have seen first hand the odd behavior of the big bucks. Their unpredictability is part of the challenge.
Get Robby Denning's book. He is truly a master at big MD. Even at his skill level, you can see him get mad, frustrated, euphoric, and everything in between.
Go hunt the unit you want to hunt even when you don't draw the tag. Nothing says you can't glass and profile your area for a number of years before you even draw the tag. When you don't have the pressure of actually harvesting an animal, your perspective and the things you observe really change.
The real reason you are a crumby MD hunter is:
You have been so successful sheep hunting, you have brought yourself bad karma.