In Finland the average amount of data transferred per SIM card is 17.3GB/month

Probably more down to limited competition in the US, honestly. Comparing costs across Western Europe, it’s hard to make the case that it’s an infrastructure cost problem; Germany (dense) is more expensive than Ireland (non-dense) which is more expensive than the UK (dense) which is more expensive than Finland (very non-dense).

Being fairly active on social media; especially GIF or video heavy websites will see you churn through 1-2gb a day easily.

I thought it was well known that MVNOs are on lower QoS/prioritisation than the carrier's own main brand(s)?

A mate works for Optus and had for a while a bunch of different iPhones of the same generation for testing.

Each had the same OS version/etc.

One on Optus Business, one on Retail Postpaid and one on a reseller (iirc Virgin).

Speed tests side by side were pretty interesting. You could quite clearly see the business service was getting prioritisation over all the others. Retail was generally better than the Reseller by quite a margin. Some locations (like shopping centres) would restrict the reseller from working at all, and retail would be clamped down on bandwidth.

I never exceeded 1GB of mobile data, personal and work combined, literally ever. But I can totally understand how one reaches these figures without doing anything weird: video call meetings, video streaming while commuting or traveling, music streaming throughout the day, maybe also work via tethering when not in the office or at home... it's just that one can choose to not do these things.

On the one hand, I feel like I'm preaching and practicing abstinence by doing things like downloading videos that I want to watch in the bus ahead of time over WiFi. On the other, long-range mobile data only works because we're not all using it at the same time, that's why we we meter it per month: it's a poor man's way of limiting concurrent usage while allowing bursty traffic and keeping the limits understandable to consumers. If you use a lot of data or need a lot of bandwidth reliably (e.g. IT company), running a local network yourself is the obvious way to go today. But with small cells coming to a bus stop near you, and seeing just how easy mobile data is compared to WiFi that can be out of range more easily (or you may be connected to a faraway access point), can be down and nobody is on call to fix it (in a company, someone might be on call for WiFi, but at home?), etc., it seems clear that for 98-99% of people and 90-95% of companies, using mobile data exclusively is the medium-term future (let's say around 2040).

And if it is the future, and since I use anywhere between 50GB and 2TB per month in data on my home internet connection (not counting others in the house), mobile data will need to handle such figures per person as well. More, even, because it will be in the future.

Someone having a 20GB+ mobile data plan is not exactly weird to me, even if with a little bit of foresight you can limit your usage to 1-2GB a month (and that still allows for quite a bit of video calling and occasional videos on the go) and save a bunch of money in 2020 (something on the order of subscribing to both netflix and spotify premium).

The left side of the chart is a surprising cohort, hardly the usual suspects when it comes to being behind the curve. There’s the US, sure, but it’s actually slightly ahead of Norway, and significantly ahead of both Canada and Japan!

You have two Scandinavian countries on opposite ends of the spectrum, two east Asian countries on opposite ends, and even two countries with significantly large landmass (look at Russia only two spots short of Korea). What gives?