So, page 72 on this, can't remember if we've tackled this... subject from this angle, but let's try it.
Is D&D 5e doing good as a product?
Not could it do better, not is it as good as it used to be, not is it better than it used to be, not are you happy, not should it go faster or slower or sideways or if everything should be blue and feature the flying purple people eater.
Is D&D 5e a success as a product that sells and makes the company money?
Because if you have a different answer to that than the people you are debating, you need to cover that basic difference in starting positions.