Even outside of US, 40h is standard, some places have 35 hour work week. 30 is less than 4 days a week, or 5x6h. I actually think that _might_ be more efficient _and_ healthier, but it's unusually little, I think it's a typo.

in the UK 37.5 after accounting for lunch is common at BT it was 36 hours a week on average (not counting lunch).

40 hours is the target. In practice, most salaried employees work around 50-60 hours a week -- more if you count checking and responding to email after work / pager duty / etc

While I'm aware some would call this a rather contrarian opinion, I truly believe that if you're in a salaried position and routinely required to work 45 or more hours a week, whether by actual mandate or "but that's just what we all do here" cultural pressure, there is something wrong with that company, more than likely starting at the top. Many companies have extraordinary crunch periods for one reason or another, and that's fine, but if you're in a crunch period more often than you aren't, that's no longer extraordinary.

I don't think that is true in general. Heavily depends on the employer, industry and country. Also unions play a big part in worktime.