As with seat selection, my opinion is the best model is not free WiFi for all but a BA-like charge with this waived for status members (or maybe fully flex tickets also). The charge doesn’t need to be much (just a few £) but it helps to ensure those who don’t value WiFi access at that much but are happy to hog all the bandwidth playing TikTok videos if it’s free don’t do so. The airlines I fly that offer free WiFi or even free WiFi for all business class passengers on longhaul flights generally have borderline unusable WiFi for anything but sending / receiving emails as a result of this dynamic.

Domestic US flights where it’s much easier and cheaper to secure consistent WiFi then sure, free WiFi for all.