Interviewing is such a crapshoot; just because someone doesn't make the cut the first time, doesn't mean they weren't the better candidate.

That's one reason I hate the "just hire the best person" argument against diversity; usually "the best person" is entirely non-obvious.

Google, Facebook, and Amazon have made a sport of shoving people through their interview pipeline multiple times.

They'll have openings again in the future, and maybe at that time their desires and your skills will be a better match.

Especially when interviewing for non-intro-level stuff...

usually there's only a few open positions. after a long process of phone screens and on-sites, you might have five viable candidates but only two slots at that particular time. if you would have been happy to hire any of the remaining three if the first two didn't accept your offer, you might encourage them to apply again later.

They do want it. A strong signal is when a weak candidate comes back a year later and kicks ass.