I'm not sure I agree. For me it was almost unbearably sad. I cried my eyes out at the end (as did everyone else in the cinema audience - including one girl nearby who I saw being comforted by her boyfriend, literally sobbing).
Also, this film contains one of my all time favourite pop records: Always on My Mind by Pet Shop Boys (a number one smash in the Christmas of 1987, so a great bit of period detail).
Great review. My review is here, if you're interested: Film Review — All of Us Strangers | Simon Dillon Cinema (medium.com)