Can't edit my original comment, but I guess maybe I was wrong. I went through a long security line with x-ray and metal detector, but I was going between Paris and UK. It also had passport controls for leaving France and entering UK, all done at Gare du Nord (nice because at St Pancras we were able to just walk right out without any more hassle).
I had read some reviews saying Eurostar security was airport like on all routes, but maybe I was just reading some other schmuck's experience on an international route like mine :-). Hopefully anyone reading my comment reads a little farther so they are better informed.
And so, I amend my previous comment. I'd be satisfied with an LNER equivalent, but if I can get Eurostar speeds at LNER convenience, I definitely want that!
I wonder how much the UK paid for the LNER lines, e.g. from King's Cross up to Waverley Station in Edinburgh. Not that it has any bearing on US costs, but I'm curious. Here everything is just stupidly expensive to build, and pretty much any stakeholder can derail the whole thing, even the tiny ones. I'm not a big fan of using eminent domain but there are times when it is the sensible choice.