Whilst they of course are getting commission on onboard sales, and much better rates than ba Crew do, it is all one cabin, so the whole Crew can come out which speeds up the service massively and allows 2-3 passes, but the main point is their offering, I can’t speak for Jet 2, only for EasyJet, they do offer decent products and some readers may laugh off a ham and cheese toastie or a bacon roll, but let’s face it, it’s much better what BA offers in ET food wise. They also do meal deals and drinks combos at discounted rates and a full duty free service. Some routes, more than others on LS and FR are prone to disruptive behaviour for one reason or another, not that I hear that much on U2.
But the product for sale onboard on EasyJet is far superior what BA are offering, decent quality and a good range of items whilst BA can be very limited and stingy on loading, so actually the crew haven’t got that much to sell.

Cabin baggage is a different matter, BA dug their own grave there and let the bun fight start at the gate whilst EasyJet and others are having a no nonsense approach, you paid for that wheelie bag, it comes on, if not it won’t, you have excess baggage pay up or don’t travel whilst fa r too often BA is too lenient and then those who do comply are in a lower boarding group need to gate check their bag, but that’s a different matter which as been discussed widely enough for BA.