True, I did mean “limited way” in various limits (I was just too lazy to research & quote all the exceptions).
As one counter-example - I arrived in Switzerland at 25 and could’ve*1 paid the missing years (I think it would’ve been CHF 400 p.a., the minimalbeitrag since I had been a student with no income), but yes, it was because I was/am a Papierli-Schweizer.
*1 I didn’t, I was broke and didn’t think of AHV at 25.
I would recommend paying it to my younger self now though, I suppose.