I think it got its start in the '70s when those sort of niceties were a worthwhile trade-off for the ability to take a small family on a camping trip around Sweden. I expect a second vehicle dedicated to touring and camping wasn’t realistic from a financial perspective for most people back then.
IMO a lot of Swedish stuff is odd (Saabs and Volvos for example) ‘til you see it in a the context of Sweden and it’s people. I read somewhere that Ikea products were designed and packaged so that any product would fit in the back of a Saab. And the back seats of a Saab 900 fold down to give a perfectly level load bay about 6’ long. (I’m not sure the first of those factoids is true, but the second is.)
In a similar vein to the Toppola, there was a small timber yacht, the Nordic Folkboat designed to be affordable and to fit a family of two adults and two children.
It seems to me that Swedish (maybe Nordic) culture places a lot of emphasis on freedom and quality of life.
The weirdest thing about Sweden? Someone can cycle to the main train station in the capital city, prop their bicycle on its stand and walk away from it (without locking it) safe in the expectation that it will still be there when they return in the evening.
It’s heavenly.