bet he was flying on a Jet2 ticket and paid his money to Jet2, if this was a short notice emergency substitution you might have a point but it isn't, so shouldn't be a case of being unlucky - Jet2 should offer a consistent product.
i agree that none of these airlines should be leasing something that doesnt come close or on par to what they offer on their own aircraft ! The prices are the same across the board and no one gets a cheaper holiday for flying on a leased aircraft , End of the day the majority of passengers havent got a clue about leasing aircraft so their experience will if bad will play a part in their next holiday