2 kinds of love and the ending of "The apartment"

So I watched "The apartment" again last night, about 24 hours after the 1st time, with immense pleasure.
I suppose there are tons of things one can write about when one discusses "The apartment": the dialogue, the plot, the wit, the humour, Shirley Maclaine's sweetness and melancholic air, the characterisation of C. C. Baxter (aka Bud), the doctor's talk on being a mensch, the repulsiveness of Sheldrake and the other 4 men, the suffix "wise", etc.
But I'd like to focus on the ending. "The apartment" is reminiscent of an essay on the 2 kinds of love in "Anna Karenina" and "Fathers and sons", the 1st one is romantic, passionate love, which can be tormenting or destructive (Vronsky- Anna Karenina, Bazarov- Anna Odintsova), the 2nd one is prosaic, intimate love, between 2 people who may not feel passionate about each other but who have trust and understanding and who find happiness in being together (Levin- Kitty, Arkady- Katya). I'm not against romantic love, but (according to some books I've read and some films I've watched) methinks, the fact that 2 people love each other doesn't necessarily mean that they can be happy together. "The apartment", albeit quite different, does seem to make the same point. In the end, there is no kiss, there is no embrace, there is not 1 saccharine bit, such things are not for Bud and Fran. Billy Wilder rejects sentimentalism and refuses to give the audience the sugary, cutesy ending they expect, but a realistic and unsentimental yet fantastic one. "The apartment" makes me think of the films I've seen which follow the formula that all such scenes (when one realises who one's true love is) must have kisses and embraces and tears and smiles of happiness, always. "The apartment" is an antithesis to such platitudinous mushiness. 
Its ending, especially the last 4 words, is fantastic. It doesn't follow a formula. It's closer to life. It's unforgettable.