Ben & Jerry makes very tasty vegan ice cream, for example. Cow milk is not a necessity for ice cream, same way as dog milk, rat milk, giraffe milk, hippo milk, or cat milk isn't.
What you appreciate is fat content, not some magical taste ingredient from milk. So you could your ice cream from coconut milk or soya milk or hemp milk or almond milk and it would taste good too.
> converts otherwise inedible biomass into human food
It's also a leading driver of deforestation, one of the biggest polluters (greenhouse gases & eutrophication), responsible for soil erosion and collapsing biodiversity, etc. etc.
We could afforest and rewild those pastures and store entire 1.5C carbon budget in those forests (thus stopping climate change and biodiversity loss).
> would the industry that would take its place if it didn't exist be just as polluting to provide all those calories
Not at all. https://ourworldindata.org/land-use-diets
> no dairy, no pizza. and who would want to live in a reality without pizza
Pizza base is vegan. Do you know vegans have cheese, and for some (carnists and vegetarians) it tastes even better than the "real thing"?
And as bonus it's sustainable and not destroying the earth for our descendants.
Make it from plants and it's another story, but until then ...