Just rambling, didn't want to have FP commenters all over it... Based on
I have trouble imagining that they will continue to "always magically find an infinite field of oil somewhere else". At some point that magic is going to run out. Oil is a finite resource!
Next up will be natural gas. CNG will slowly replace oil. Perhaps battery tech will move along too, people will find some way to store electricity so that plug-in CNG/battery style vehicles will become a thing in a few decades. But NG is also a finite resource, even though it's massive.
Like everything else, make it plentiful and people will use/abuse it until it's mostly gone. I totally envision a mad-max style future when it happens, except for our denser populations. That will add some complication to the full-on mad max future, but if things get heated enough (get enough angry people together and it may) a nuke or several may quickly diminish the population to mad-max levels. Who knows, maybe today's highways will be replaced by ultra-efficient public transportation and we will all be saved!
Someday we will run out of oil. Our generation? The next? Or the one after that?
After we run out of [oil, NG, fill in whatever is next], and only then, will people return to local farming, local production, local support. Communications will improve, global communication will only get better. But transportation will get worse.
I'm not trying to be pessimistic, it takes a crisis to make things change. But I would love to see what the world's transportation and energy infrastructure is like in 100 years.