Count me among those I guess. I can pay for tips and wifi (which is a huge profit center itself for the cruise lines), and bring my own soft drinks onboard and save a lot over the cost of 2 plus packages, so it works for us. On our current 10 day cruise plus would be $1200 and I paid $520 for tips and wifi so they are still making a lot of profit off me, and that's okay. You can't cruise without expecting them to.
As I said, a coffee/soda package with tips and wifi for say $35 a day would make me think about it, although they would need to offer coke zero and sprite zero for me to consider it. It would still cost me about $150 more than I spend now (bringing my own onboard), but I might find that worth it for the convenience.
It's all about everyone's threshold for the value they perceive in what the onboard costs are. No issue at all for me if someone doesn't drink and finds the plus a good value, that's everyone's individual decision.