That's a Vince move. He's the Richard so hellbent on total domination that he scheduled PPV's to compete with AEW, threw NXT on TV to compete with AEW on Wednesday nights, overpaid marginal wrestlers in an effort to keep AEW from filling out their roster, etc. AEW has weathered everything Vince threw at them and done quite well, so some gloating does feel justified.
Having said that, short-term WWE better hope and pray that Dynamite doesn't move to Mondays. Sure, AEW's ratings would suffer, but I guarantee WWE RAW ratings would immediately drop at least 20% with a commensurate drop in stock price, and their shareholders would raise all sorts of hell.
Long term, though, I could see the competition elevating both and drawing greater ratings for both a la the Monday Night Wars.