Sweden's population is only around 11 million people, and you're geographically concentrated in the southern mainland provinces or near Stockholm. Both of those make thing a lot more practical to manage and make it a lot harder to abuse because you don't have the scale to make profit as attractive, or the distance to make oversight more difficult. You're also relatively culturally similar.
It doesn't seem like those should matter so much, but it really does make everything about democracy easier.
Things get much weirder when the population isn't so low or isn't relatively concentrated.
I mean, I can do all my voting, tax filings, etc. etc. All the way from Mexico, with no issues. You're right that most of that must of the Swedish population resides in the south, but, as someone who grew up in Northern Sweden, it's not like we're marginalised or anything, not really.