Losing the plot in a dissatisfying read

When I give precious time to reading a book, I resent it if I am left with a sense of pointless meaningless at the end. I kept on turning the pages of Douglas Kennedy's The Woman in the Fifth because it is very readable and any book set in Paris involving lots of visits to pretentious meaningful films can't be all bad. After finishing it I had a real sense of dissatisfaction. The plot seemed to lack any creative resolution and the message seems to be that the main character will have to give in to the forces of fear and vengeance in order that retribution not be meted out on those he loves. The novel seemed to have lost its own plot. (Probably there was some deep allusion to Bunuel or Godard that I missed, but hey I still didn't like it.)
So I realise that although I'm fine with unhappy, terrible, sad, enigmatic or tragic endings, I'm not really ok with endings that don't work or haven't been worked on. I wonder what his editor was thinking of - perhaps - ah well on the strength of his other books this one will sell anyway. Most books that I don't like never get finished, I just give up on them. Usually I'm fairly upbeat about whatever I happen to be reading, what the French call "bon public", I'm just so happy to have found something to read. So I suppose it was just as well that it was only one of the six books I got for 5 euros. Probably I should just stop moaning.