Seriously, why is this idea being thrown around? It's not based in reality, and just fuels into pessimism. I'm American, so I'll mostly focus on what I'm seeing here.
There has been so much progress, even just over the past decade. I think the reason that it feels like not much is being done is because the United States is so Massive. Even just New York can contain Beligum, Switzerland and the netherlands.
Looking at the US on a macro scale could give someone a picture of a country eternally doomed to have shitty transit and suburban sprawl forever. Thankfully, we have a beautiful think called local government.
There are a good number of places that you can go in the US that are very walkable and have good transit. Sure, it's not on the level of Europe, but it's definitely a good starting point if we're talking about progress. Especially if we're talking about progress within our lifetimes.
There are a lot of cool projects going on in the US right now, such as new rail lines, rail extensions, new BRT lines, and work being done on density. And of course roped into that we can't forget about the massive California High-Speed Rail project, which if successful could have major implications for rail in the United States at large.
Is this enough? No. But it is real progress, and a sign that we're at the beginning of real change in this country for transit and walkability.
And if you still think the US is shit and you really feel inclined to move out of your current suburban hell hole, you don't even have to leave the US to do so. There are cities where you can go today in the US where you don't have to own a car and can get around by walking. Not everything is a 6 lane stroad with giant parking lots and dead strip malls. We have DC, Philly, Boston and NYC as prime examples, which may not seem like much but NYC alone has 8.8 million people and could sure as shit fit way more.
Sure, we may never live to see the whole US become the netherlands, but I don't think it's unrealistic to think that certain places in the US could be seriously be at that level within our lifetimes.
There's no money for it, doing it requires obtaining rights of way the city doesn't have, the belt highways are built specifically to prevent this, etc, etc, etc. The amount of time it would take to build these systems is its own problem. The only way to do it would be under socialist central planning, and it absolutely wouldn't make any sense to build it into the suburban sprawl. Doing so would cement that sprawl by building additional infrastructure into a footprint that logistically is unsustainable anyway.