Why does the slippery slope concept surprise you? It actually happens often - banning smoking indoors, for example - started in just one city, once they tweaked the model and overcame the legal challenges, it spread rather quickly. Legalized casinos, same thing. Uber, drinking age, pot legalization, more. Why would toll roads or congestion pricing be different? (Idaho's Sun Valley probably already implements something similar). And ICE vehicles are definitely in many politicians' crosshairs, if you don't already see that coming in the next decade, you aren't really looking.
I think the slippery slope has long happened and also gone away.
There are a ton of roads with "turnpike" or "pike" in their name. Some cost money [1] others are free. What's the big difference between NYC's congestion pricing and the Florida Pike?
I guess you can fight congestion pricing in order to slow the spread of toll roads but it's not the beginning of a slipper slope. Usage fees are a very old concept (price discrimination by time is pretty old as well).
Well, yes. Once you demonstrate that a good idea works and the doom doesn't come to pass, it gets copied. It's easy to claim that something doesn't work when nobody's doing it. Making the same claims when someone nearby is doing it and it works requires a higher level of reality-denial. Now, there's a lot of reality-denial to go round in politics these days, but occasionally a good policy slips through.
The EU ICE phaseout is set for 2035.
The argument that because a few things have spread, things in general are likely to spread is itself a slippery slope argument.
> Why would toll roads or congestion pricing be different?
The answer is actually quite simple: It won't be different. Prove to me it won't spread, because almost every new tax spreads.
When is the last time a tax has existed in one state, and not spread to other states within 5 years?
These would be examples of normalization, not a slippery slope. The OP's example makes this clear (from "congestion pricing in NYC" to "they're going to take my car," not "congestion pricing in NYC" to "congestion pricing elsewhere").
(Regardless, I think the answer is simple: congestion pricing is only economically viable when an area is simultaneously congested and has alternative transportation methods that would prevent the local economy from collapsing. NYC is one of a very small handful of cities in the US where this is true, although that's largely a function of 80 years of car-centric design. Maybe it will change.)