(We kept part of our grass for exactly that reason but it helps that we don't have to water the lawn here. With added clover I'm quite happy with it.)
What I don't understand is, is the need for huge front lawns. It's all the work with none of the benefits. Just a waste of space really. People don't use them the same way at all.
But it's true that a lot of people don't use their front yards for much, except perhaps as a noise buffer from the road. If you go a non-lawn route, you'll need to be careful to maintain it in a way that doesn't encourage intervention by neighbors, municipalities, etc. On the other hand, I'm rewilding a bit of my back, and nobody says anything.
Have you considered that some people just like looking at it and that's enough? It's their private property after all.
They may not be the reason, but HOAs are absolutely the cause of outdated, environmentally unsustainable, bullshit lawn requirements.
Lots of things are inexpensive when ignoring externalities.
(I'm assuming an area where grass actually fits the environment. If grass won't just grow then that's a problem that doesn't need more explanation.)
It took years for the neighborhood to convince the HOA to allow other kinds of ground cover (jasmine, frog fruit, etc.). In the mean time, people were paying yearly to resod with new grass, or have to pay fines that cost more than just paying for new sod.