How's the view from up there? Allow me to add a dose of reality to your rosey colored utopian perspective:

You're absolutely right about proper lifting techniques and the importance of sticking to the fundamentals. What you do not factor into your criticism is the effort many screeners exert trying moving as many bags out as possible without compromising the integrity of the screening process. Screeners want to do a good job, and nobody wants bags to miss a flight. This is where their zeal overcomes fundamental things like proper lifting techniques. As I pointed out earlier, there are no immediate symptoms when lifting improperly, and this tends to give screeners a false impression that they can get away with cheating on their lifting techniques. Groin injuries, muscle pulls and other injuries are gradual. They don't become evident until either while actually lifting a bag or doing something else completely unrelated to baggage screening such as getting off of a stool or getting out of a car. This gives the misimpression that the injury was caused by getting off that stool or out of the car rather than the fact that it was due to the gradual wear and tear that comes from cheating on proper lifting techniques every day at the airport.

You're right that this requires better training and employee awareness of injuries that come from poor lifting techniques. And I have to credit TSA for trying to increase screener awareness of this topic. However, during the "heat of battle," a lot of that is forgotten as screeners focus their attention on getting as many bags out as possible.