What was your wife trying to do with this exercise?

Pretend to give half a shit about him without actually giving half a shit about him? Look like a decent spouse without having to put the effort required for that. Have her cake and eat it too - get the loving couple treatment after putting in the friendship effort only, at best.

one thing you can at least take from all this is that she's looking for solutions.

How can you even say stuff like that, that is not very observant or smart thing to say, sorry - she completely forgot about the whole thing, how can anyone read that and then get confused as to say she's trying to do anything when in fact it fell through the cracks utterly... She is not being a good partner and that's bad. There is no point in defending her for it... She dropped the ball completely, how will cutting her even more slack going to fix anything?

All evidence points towards her having zero attraction to him, to the point that she forgot about the whole thing. Even having him on her mind is too much effort for her, she literally cannot hold in her mind a mere thought about him for longer than half a day...

Her comment "not to give up on her" shows at least mental effort on her end

It shows nothing, you are making stuff up in order to excuse her. What is "mental effort" anyway? Does it count for anything? What exactly separates "mental effort" from empty words?