Just as the 737 NG was a reaction to the 320ceo...the MAX was a reaction to the 320neo....
BA had been focused on the 787, 748 and was not planning the NSA until 2030 and after the NMA....then the neo series caught them off guard.
Currently with the 321 XLR, I wonder if BA is serious about a re-hab of the 767...ie the 767XF a rehab 767-300 (right now a freighter...but....)
https://www.flightglobal.com/program...134757.article
Sad but true...