The main attempt to break into the US market came with Carry On Follow That Camel with Phil Silvers in a role that was similar to his Sergeant Bilko type character. The Carry On's represented a very particular saucy postcard type of British humour that was quite popular and maybe still is with people of an older generation in the UK (is it popular with young people of today?). LOTSW and other Roy Clarke comedies also have a touch of that and why would anyone expect any different as he is a comedy writer from that era? The way Compo chases after Nora would not be out of place in a Carry on for instance, or for that matter the Howard, Marina relationship. 1960's to 1980's British comedy always had that innuendo element about and was often quite openly sexist and racist, it reflected the times.
What is interesting is that perhaps ones of the kings of 70's innuendo, Benny Hill, was quite popular in the US.
The Telegraph reported in his obituary: "By 1985 not a single day would pass without The Benny Hill Show being screened somewhere in America, and many stations would broadcast the programme twice a night. At San Jose penitentiary the prisoners threatened mayhem unless they were allowed to watch him."
Benny Hill was far more saucy with his characters than the Carry On's ever were. So why did the Americans like Benny Hill and his dirty old men type characters (most of the male actors who appeared in his shows were quite old, while the women were very young glamour girl types)?