Trigger systems like Vanek, glock triggers, and the like

I see a lot of Glock trigger systems online. Most of them seem to be polished or "tuned"oem parts with a minus connector. Some like the Vanek seem to go so far as to change spring weights, strikers and add setscrews to the trigger housing. Outside of that paying $150-200.00 on a basically stock trigger seems foolish. Am I alone here or am I just missing the point?