As you know, the friendship that Elly and Annie shared faded away while the one she had with Connie grew stronger. It would be far too easy to blame that on Elly's inability to get a handle on their marital problems; she proved she had no trouble poking her nose in where it didn't belong when she and the others helped wreck Anthony's first marriage. The reason I think that Elly treats Annie like a second-tier chum is her distaste at Annie's refusal to see why her children should thank her for all the things she did for them. Connie's seething frustration at how Lawrence's lifestyle inconveniently deprives her of the chance to fuss over grandchildren and race around like an idiot at a wedding makes her a better person than Annie who doesn't much see why her children owe her debts they must pay and pay and pay. Since Annie is a better parent than either Connie or Elly, she's not friend material in the eyes of Flapandhonk.