I think the reason you don't see British restaurants that much in the US isn't that it's bad food, it's that a lot of traditional British dishes have sufficiently close equivalents in "down-home cookin'" American restaurants (as in a roast beef dinner) or in bar food (as in fish and chips) that there isn't much demand for anything more specialized. The full fry-up breakfast is something isn't so easily found here, but near me there's at least one themed pub that does serve one (although it's Irish rather than English).

I think it was just never made restaurant food? You don't really get them in the UK either. A restaurant that doesn't bill itself as x country's cuisine is basically going to be French/in that tradition. Closest you can get is a chip shop or a 'real ales • good food' pub.