Why does it seem like so many people are constantly searching for different broadheads?

What kind of problems are people having with simple straight forward broadheads thunderhead,muzzy,montec,slick trick etc.?

What is it these simple heads are not doing for you?

I mean I have shot a LOT of deer with these simple broadheads and I don't ever recall thinking "I sure wish I had a better broadhead" they work pretty great for me.