According to Poets&Quants, for Mendoza, “In Fall 2018, the school received 4,477 application to join the undergraduate business program, and in total, 840 students were admitted”.
You can decide how competitive you want to be. (I don’t know if “most” have 4 years of science but I think these numbers give you some perspective: do you need “most” applicants to have 4 years of science, or just the 840 ahead of you for it to make a difference to your own chances?)
Again, I think you seem to be struggling with deciding between what you feel you “should” do, and what you want to do. I don’t think your entire high school experience should be tailored around possible admission to a handful of colleges, but at the same time you need to understand what you’re taking off the table by not following the most competitive course for admissions. There are still many good colleges out there if you choose a somewhat less competitive path and it doesn’t work out for one of your top 3 choices.