Doctorates in the EU are supposed to take no more than four years if studied full-time; I'll complete mine in three. Of course, the corollary is that one generally already has a master's degree when entering, cutting two years (in the American system) off the front end and basically setting you up with all the coursework you need.
From the point of view of a (1980s admittedly) physical sciences PhD from the UK, that situation's almost unrecognisable:firstly, there was no formally-taught component (there were a couple of Americans in my intake, but they'd both done a year of taught postgrad on top of a BS, which more or less brought them up to speed - there were also research talks and optional specialist short courses, but these were not mandatory); secondly, the existence of grant money to live off meant that we spent no more than 4-8 hours/week in term time running labs or tutorials for undergrads (this was paid reasonably well - if we were lucky enough to interest an undergrad in doing a dissertation in our area in the last term before their finals, we got to work quite closely with them, but weren't paid); and finally, if you didn't submit your thesis within a calendar year of the end of the three years and three months, you needed a fairly hard-to-get special dispensation (I just missed having to do this as our daughter was born a couple of months before my funding ran out - I'd already lost some time because of changing topics when my first supervisor went back to Texas - and then I lost some more time because I started my first post-doc down in Leeds before I'd formally submitted in Edinburgh: no proper internet in those days meant dialing in long distance (at cost and 300 baud) to write up, and frequent train journeys back to Edinburgh at weekends).
But I'm not going to cite the Three Yorkshiremen sketch: we may have had temporal constraints, and not lost much time to teaching commitments, but we had a grant to live on that was almost as much as we'd have been getting in unemployment benefit (slightly better if you were over 25 - the postgrad grant had a "mature student" allowance that cut in then, or under 21 - unemployment benefit was lower for ages 16 to 21.
And all this was in the socialist hell that was Thatcher's Britain....
Or your advisor could take your revisions and disappear with them repeatedly, for months at a time. That's how I've spent the last six months. That adds some time to the process even if you DO go to the school to complain.