When arriving at ATL earlier this month, the FA's arrival announcement included: "if you're connecting to another airline here, good luck with that." I thought it was quite tone deaf considering how badly WN screwed up only weeks before. Sure DL has had operational issues, but your own passengers had to book replacement tickets on them recently because of your failures.
And the DOT focus on scheduling more flights than can be staffed is an easy out for WN. Cascading delays and the inability to reroute planes and crews was a bigger issue. Since all the planes and crews are largely interchangable, it seems like it'd be easy to reassign them to another destination to keep things moving. Of course it's not that easy since crew duty hours and aircraft hours until next maintenance check and where that check can occur also need to be considered.