On the other hand, DSL and cable connections in Central Europe have had these kinds of limits for ages, and the flat fee and "fair-use" style contracts have only been offered on a broad scale for the last 2-3 years or so. (my parents & sister were on a 2.5GB/month contract until about 1½ years ago)

I suppose it's not held up the massive expansion of broadband as much here because the alternative, dialup, is even more expensive, at generally between €0.01 to €0.015 (~$0.015-$0.02) per minute. We've always been used to paying a premium for internet access, so when something comes along that's better value for money, more people jump on board.

The capped or pay-per-megabyte contracts are still the norm on mobile (EDGE, 3G/HSDPA/HSUPA) internet access though. But mobile communications contracts in general already have pretty draconian terms in my experience. (minimum runtime 24 months, small print overload, etc., at least you aren't charged for receiving calls/texts these days anymore)