I think this is mostly a problem in the united states. I'm from Europe, and everytime I visit USA I am struck by how huge most of the cars are. Like, why?
1. Obama-era CAFE fuel standard rules made required MPG go up over time for different classes of vehicle. Except if your vehicle had a larger footprint, it had more lenient standards. The simplest way to stay compliant was to make larger vehicles. I think if they wanted the actually-desired outcome they should have just raised the federal gasoline tax, which has not been raised since the 90's, but they probably assumed that was untenable so we are left with unintended consequences.
2. The IIHS produces crash test ratings that manufacturers tout here and does not score cars worse if they are more dangerous to pedestrians. Nor do they take into account the other car in the collision. So to get excellent ratings makes an arms race of bigger-ness. Automakers started adding a lot of weight to vehicles, and side/curtain airbags that made the A-pillar larger (Between door window and windshield). Even formerly small cars now feel huge. It's hard to buy a truly small truck anymore.
Even cars of the mid-2000s have this pillar sufficiently large to completely block the view of pedestrians and vehicles under certain conditions. This is, I'd argue, a contributing factor in the modern preference for taller vehicles- the visibility is equally poor, but being higher up lets people believe they can see more out front and they "win" in sightline contests with other cars.
>Automakers started adding a lot of weight to vehicles
Note also that electric cars in particular are significantly heavier than combustion ones; as such they take more effort to stop and are even more dangerous to other cars in crashes.
Oh, and since electric cars are inherently heavier, the roof has to be stronger to maintain the same rollover protection, which also means the A-pillars and blind spots will continue to get larger.
>they should have just raised the federal gasoline tax
If you do that you run into price-sensitive agricultural users. Other countries exempt those users with marked gas to detect tax fraud, but that requires legislative action (marked gas is illegal in the US) and new infrastructure to support it to the point where it might not have been worth it.
Also, the chicken tax means unless the light truck is domestically produced it's not worth it, so only a select few automakers could really make a run at it (especially in the context of safety requirements that don't scale).
Because of some historical accidents (see https://en.wikipedia.org/wiki/Chicken_tax) normal cars are regulated more tightly than SUVs in the US. That makes SUVs cheaper to produce.
So people, like families, that needed a big car moved from station wagons to SUVs.
The rest is more historical accidents and consumer preferences.
(Some of the regulations in question here are really silly. Especially the CAFE standards which are ostensibly supposed to regulate emissions. But they do it in a really round-about way. A sane way to regulate emissions is to tax emissions like a CO2, or something that directly correlates with producing more emissions (like a petrol tax).
Instead the US goes the insane route: CAFE standards take an average of the vehicles produced by a company, and give companies some incentives based on that average. Of course, they also add extra loopholes, like the SUV exemption.
SUVs also get exemptions for passenger and pedestrian safety standards.)
Wtf? What's the rationale behind this?
Basically, the originally justification was that stuff like farm trucks shouldn't be burdened by extra regulations. Public choice theory explains where it went from there.
They also tend to be more dangerous for family, and neighbors nearby.