I don't think the crash test requirements in the US are tougher than those in Europe. European cars had side impact protection before US cars. Safety requirements are not the reason some brands don't make it to the US market. The main reason is the cost of building a resale and service network. Most european cars are designed for their own market (narrow streets, narrow and twisty roads, restricted spaces for parking and driving) and are ill suited for the US markets. So the cost of building a dealer network on such a large (geographically) market is prohibitive for most european companies. The exceptions are high-end brands that sell at a premium and have little competition from us companies (bmw, mercedes, porsche, ferrari...), or companies that produce in the US (Toyota...), or Mexico (VW). It also requires most of these companies to completely change their culture: In France, for instance, you buy a car before seing it, you place an order for a specific color and trim and wait around 2 to 3 months before delievery. Nobody would accept that in the US, if the car is not ready for you to drive within an hour the deal will go to another dealer.
It takes a lot less to export bikes to the US and the market supports margins large enough to make it attractive. The problem is that the US produces great and world recognized high-end bikes as well (Trek, Specialized, Litespeed). On top of that it's difficult to convince most US buyers that European bikes are better when the last 6 Tour de France, supposed to be the greatest and toughest bike race in the world, have been won on a US bike. That means that only top end European bike makers can even dream of reaching the US market and only for a part of a very tiny and highly knowledgeable (some would say snobbish) consumer base. Most need to provide large enough productions (Bianchi, Look), history (Colnago, Bianchi, mostly Italian builders), or recent racing victories or connections (Merckx, Time).
As a Frenchman I like my Time bike. It's fantastic but I am sure a Trek or Litespeed would be fantastic as well.