Thanks.
I was brought up to speed at Heathrow, Gatwick, and Amsterdam where 2.5 NM was the limit. When flying to that spacing the landing clearance would arrive 500-150 feet, very frequently you hear the AP disengage bell with the readback and RA call of minimums in the background.
Having convinced myself the US is more fluid than I could bear (many Oskosh videos, LAHSO, NTZ visuals to SFO, JFK ATC tapes ...), I presumed that 'line-up, approaching traffic 3 NM' was a fairly standard call for SW crew they'd get 4x per duty day. Happy to learn the real picture from you.
For the rest, I am quite convinced we're talking the same albeit with differently angled sentences.
there wasn’t any luck involved here, because, thankfully, FedEx knew
Exactly what I had in mind, but it only is a figure of speech: "thankfully" implies "luck" (good coincidence). A systematic layer/backup is something always there, such as the incursion alerting system in the NYC case.
Or a go-around procedure instructed by ATC to re-establish separation (did not happen). Also, I note the G/A itself did not de-conflict the situation sufficiently, although their beyond-duty call for the SWA to stop would have had if understood and acted upon.
Only once I saw an A320 go missed from the threshold as the departing passed the runway midpoint on the roll ... and I don't think any of the crew / ATC would ever do that again.