LORs from profs are not pointless. They can tell a lot about you. The problem is simply that in larger, lower-division courses it's often difficult for a prof to know every student. As a result, the most engaging, determined, and focused students are likely to be the ones who the prof gets to know and can write a decent LOR for. While the system is certainly imperfect, it does serve a function.
As for volunteering, etc. being worthless, while many students do do these things simply b/c "it's required," I don't think this is always the case. At least some (hopefully most) of us can honestly say we volunteer, do research, etc. b/c we love it. I won't generally take on a volunteer role that I don't feel I would fit will and if I fit a role well, I will generally enjoy it. If you don't like volunteering at a hospital or a free clinic don't do it -- find some other organization whose passion you passion and mission you share! I truly believe that your sharing a passion with the people you volunteer, research, or work for will show through in your LORs, PS, and especially your interview, so it's definitely to your advantage to find something you love. Don't just take what you can get!