I look at alternative retaurants this way...
Having them has allowed the cruise lines to lower the cost of MDR food overall and hence keep cruise prices extremely competitive. You get your cruise cheaper and can splurge on finer food when you are in the mood for it, and NOT pay for it when it doesn't matter to you.
Now - there is a cruise line with a daily food budget for everyone. Oceania and Azamara, for example have wonderful daily food and no surcharges for the "specialty restuarants."
If you want to spend more you can go to Crystal, Seabourn or Silversea, but there you are paying extra for more than just good food, you also pay extra for more space per person, more staff per person and all beverages included.
I just don't see alternative dining as a "controversial" issue once you see the logic of how it has been implemented by the cruise lines. Yes, without a doubt the average dining room food quality has diminished industry-wide over the years, but cruise prices have remained almost the same for over a decade now while the cost of fuel has gone up (what?) 500%.
It is just a different structure of dining than it used to be, but the quality is still available.