As the saying goes, you get what you pay for. And that's often true about food as well.
Particularly, quite often if you go to an ultra-cheap pizzeria, the pizzas are really, really flavorless and tasteless. They might have a really, really mild flavor, but overall they often taste like nothing.
This is actually a bit of a mystery to me. How do they do that? I'm completely serious: If I purposefully wanted to make such a flavorless pizza myself, I wouldn't know how! Even if I buy the cheapest possible ingredients at the grocery store and make a half-assed pizza, it will taste significantly better than those at most cheap pizzerias. I honestly don't know how to make such a tasteless pizza even if I wanted to.
My hypothesis is that these pizzerias don't actually get their ingredients from the same sources as grocery stores do. Instead, they get them for much cheaper from some other sources, and the quality of the ingredients is simply abysmal. So abysmal that they don't even sell them in regular stores at all. Like flour that would otherwise go to the garbage, cheese that even pigs wouldn't eat (and would likewise be thrown out), and so on. That's the only thing I can think of how to make such tasteless pizzas.