Well, looks like smart meters started appearing in US slightly later than e.g. here in Finland, around 2006-2007, so I'm not sure that explains the difference. Could be explained by lower mobile network coverage in U.S., I guess.
3x 63A is the reasonable maximum a normal consumer would want at their house. Normal houses are around 3x 32A.
Everything over that is a commercial building and they get billed with different rules and measurements due to the equipment they tend to have. Something about three phase engines and power phases in commercial lighting. I zoned out during those meetings :D
Finland has 230V, so if you're from the US with 110V the low current rating might be confusing ;-) I'd also guess that in Finland they also run three phases into each house/unit (we do in Germany), meaning that's 3*63A = 189A. (Or just shy of 400A on a 110V grid). For us that's the default grid connection you get for your house.
As for your guess: That's just a cultural thing I suppose. I've never seen outdoor meters around here.
The US is 240 volt for power purposes. The 120 volt thing is just dividing that in half - the meters don't measure that. These days most US houses get 200 amp service, but in the past 30, 60, and 100 were all common (100 is still done). I know of a few houses with more than that, but those are not normal.
3 phase is different from us split phase. In the us that would be 404 volts (or about that, I don't work with it just know it exists) or 208 volt if you that the split phase in 3 phase.
Anyway the point is 3 phase is not added in the same way as split phase. I think you know that, but I'm sure someone else doesn't.
Naw, Canadian. Cool to have 3ph at home (even without the #1 thing that fails here because we don’t have 3ph: a/c (capacitors)), but why’s your industrial supply just 400V instead of a soup of 347V, 480V and 600V?
US statistic: https://www.statista.com/statistics/676472/number-of-smart-m...
In 2005 in Finland about 7% of households had smart meters, with 80%+ coverage mandated by 2013 and actual coverage of 99.6% of under-63A meters in 2016 (Finnish sources: https://www.vttresearch.com/sites/default/files/julkaisut/mu... https://tem.fi/documents/1410877/3481825/AMR+2.0+loppuraport...).