That's true. I obviously can't speak for everyone but Americans seem to have such a bad reputation in the UK as it is and I guess it makes sense.
Still, this is a country that despite its diversity, still laps up its generic and catchy pop tunes, so I fail to understand why she's never seen much success.
Meh... a lot of American pop stars are much smaller in the UK than elsewhere
Gaga, Beyonce ect. haven't had a #1 single in the UK for years now
I think American artists sometimes have trouble breaking into the UK market simply because the UK has a strong, flourishing music scene itself. The stronger the local market, the more difficult it's obviously going to be for people who aren't from that country to make it there.
The same applies to a slightly lesser extent to countries like France, Italy, Germany, some East/Southeast European countries etc., and definitely many more around the world in general.