Multimodal is the Answer?
Some bike activists get into car-hate and think the car is the enemy.
I think that it's situational. In some cases, like when you're frequently being assaulted by idiot/lazy/ignorant/violent drivers then it's smart to consider the car as the enemy. It keeps your defensiveness up. Heck, other drivers need to consider each other as enemies. ---It's a big part of the actual and technical insanity of carland. (Driving cars a lot changes our minds, literally, in a very bad way. Sitting in those deadly boxes...)
In working on this upcoming folding bikes book it's been neat to see the car-integration and car-acceptance ideas in it. It's not about car-hate. It asks: How to make cars and bikes work best together? It says that there need to be several categories of bikes that work really well with cars, and others that work with each of the other transit modes. Train-bikes. Plane-bikes. For both long and short distance needs. Lots of bikes for lots of needs is a GOOD THING. There's no "best bike" in this scene---only a best bike for YOUR transit situation. Transit optimization is what we need, not transit us/them enemies (not all the time anyway).
We Americans live in a big country and we sometimes need to get around larger distances with groups of folks, etc., so cars come in darn handy.
I think the key might be to use them as needed. Not just as habit.
Scalable transport might be the answer. For long-distance Americans, anyway.
Is it possibly sustainable for folks (and extended family/community units) to have a variety of modes to choose from in light of the transit need. A minivan with 6 people in it going 100 miles into the countryside (not on a train-route) is pretty thrifty and sensible, it seems.
(Of course, if you're on a train-route and your schedule is amenable and your society is sensible that will likely end up the cheapest, most convenient transit means. Unless you're hauling lots more than your luggage.)
So what about having community units have access to this line-up: Minivan...utility trailer...subcompact car...motorcycle...moped...e-bike... bike...tandem...folding bike...bike trailer.
You have a quiver of transit. Pick the lowest gas mileage / reasonable solution from the options.
4 people in minivan = 100mpg per person. 2 people = 100mpg with motorcycle. 1 person = 100mpg with moped. For under 5 miles, use bikes and trailers. See?
For longer distances, you start needing to slow your life down to make bikes viable. Which is a good thing.
To ride 60 hilly miles the other day I spent $6 on food fuel. Homemade fuel brought with me would've cost $4. It took 4 hours. I could've carried 20 pounds max with me and stayed in that same time/cost range. Two people would've cost $8-$12. Of equal skill. A family would've taken most of a day and cost even more. But no oil burned. That's the economy and limits of biking.
Of course maintaining a fleet like this would be a pain. But across a neighborhood community (or extended family) it wouldn't be. If folks live within a couple miles of each other anyway.
And of course producing all these vehicles consumes a lot of energy.
But let's just consider what one bike situation that works WITH cars might be like... First, a bike that's optimized for a car DOES NOT NEED A ROOF/TRUNK RACK!!! See how radical this idea is? Many bikers have come to accept the $500 clunky, heavy add-on that they need to strap on each time they combine bike and car. This is bad! Racks are pricey, heavy, ungainly, inevitably damage both cars and bikes (most longtime rack users suffer at least one CATASTROPHIC bike damage), often very insecure (many potential weak-links for theft or damage), noisy, dirty, hurt car performance and are uneconomical for fuel mileage. Whew! A bike that folds compactly in 15 seconds and goes into a clean bag and stows INSIDE the car and still rides great if needed for longer rides: what an idea! ALL of those problems: GONE! The only cost is somewhat less trunk/interior space. If needed only for under 3 mile hops it doesn't have to ride as perfectly and so tends to be able to store smaller and faster. There are several bike options out there today for each of these car-bike parameters!