Go out and find an isolated tribe who only eats occasional wild game. Serve them grain-finished beef and grass-fed beef. Do you actually believe they will choose grass-fed over grain-fed?

I prefer meat that has been fed only grass and never buy grain-fed meat. (I eat mostly lamb, not beef.) I prefer the taste and believe it is better for my health; in particular, the omega 6 fatty acids in grains and in grain-fed meat promotes chronic inflammation. (I don't buy grains either.)

That's your n=1 opinion and it doesn't change the reality of human preferences which are clearly documented in the literature. Even the overall health outcomes associated with grass-fed are not significantly different than grain-fed. The tissue composition may be different, but not health-outcomes.