The car seat needs to be individually adjusted, especially for younger kids (different heights needs the straps in different slots, although the fine tuning can often be done on the spot).
And you're going to need every combination of ages, people have more than one child.
There are approximately 10 different car seat configurations for the various age ranges (5 actual car seats). And assuming up to 3 kids would require 1000 different cars.
There is rear facing (with 3 heights), front facing strapped (4 heights), front facing buckled, booster, and booster without back. (Although many car seats can handle 2 types in one seat. But it requires you to reinstall it.)
They buy 3 since virtually all can convert between two levels (any two adjacent levels). A rare (and expensive and heavy) few can do 3 levels in one.
But converting the seat requires rethreading the straps and other adjustments - it can take an hour to install some types if you are not familiar with it.
I'm not sure how it applies to other countries, but here at least you have to have special car seats for all children until they're aged 12. It's insane, but that's the fabulous new law they enacted. So, yeah in some cases, some parents really are buying that many seats.
And you're going to need every combination of ages, people have more than one child.
There are approximately 10 different car seat configurations for the various age ranges (5 actual car seats). And assuming up to 3 kids would require 1000 different cars.
There is rear facing (with 3 heights), front facing strapped (4 heights), front facing buckled, booster, and booster without back. (Although many car seats can handle 2 types in one seat. But it requires you to reinstall it.)