We got a BMW i3 (small, electric car) in Sep which is working fine with our 3 and 5yr old. My FIL was dead against us getting it because it's small - but within 2 months of us getting it, he'd sold his car (a Nissan Leaf) and bought his own.
Kids don't really need that much room in cars. When I was young my mum had an old-fashioned mini and I remember my mum and us 3 kids bombing up the M1 to visit family up North for a few days and it was all fine, even when we were teenagers.
I live in a suburb of London. I man a school street road closure once a week, and spend it watching lots of people dropping off their kids to school. So, so many parents with massive cars - huge Range Rovers where they really have no hope of seeing any child height people anywhere near their car. I worry a lot about climate change, and honestly find it quite sickening; all that petrol burning for the sake of transporting ginormous metal hulks around when something smaller would've been fine and probably more manouevarable and practical).
There is a snag with the BMW i3. We like camping weekends and also go to a festival once a year, and the car wouldn't fit all the camping equipment in the boot. But we have a plan: one parent will drive the stuff in the car to the campsite/festival, the other parent will take the kids on public transport. Turns out nearly everywhere we visit is 90% doable with public transport and maybe a lift or taxi to get us the last 10% of the way. Plus the kids hate long car journeys and I hate long car journeys with the kids moaning. Train fares are expensive, but probably far less expensive than buying and running a huge car all year round just for the sake of a handful of trips.
I asked my DH why SUVs are so popular, cos it baffles me. He says it's because they don't cost much more than normal size cars to make, but you can charge more for them because they're bigger, so the margin on them is better - hence car companies have been advertising and marketing them very heavily.
Engine efficiency has come on massively in the last decade, with those improvements is mpg we should be seeing transport emissions reducing in the past years but actually they're staying level. And some of this is attributed to cars just getting bigger.
In comparison household electricity consumption dropped by 18% in the UK between 2009-2019. Amazing, but true. And that's been because of LED lights and more efficient appliances. Imagine if that'd been replicated with transport?