It also depends on what you personally consider acceptable. I got around Ithaca for years with public transit and my feet. But there really wasn't anywhere I couldn't go by walking, and I usually had time to walk or I didn't have time to go at all.

In Austin, I chose my housing based on what bus lines were nearby. And biked a lot at some of the places I lived.

Neither of these places have GOOD mass transit, but they both had mass transit good enough for me.