If I understand the timeline properly, Boeing had a strategy, at least nominally: NMA, an all-new replacement for the 757. Boeing had to be brow-beat by their biggest customers to support the initiative, but at least from the outside they seemed to acquiesce.

Airbus responded with the A321XLR, betting it could reach market faster. Boeing countered by dropping NMA and trying to copy the Airbus approach of racing to market with a stretch variant of their workhorse (737 MAX vs A321neo). But Airbus was actually able to execute. A321XLR is on the verge of shipping while Boeing has been caught flat footed, again.

Also, A321XLR has significantly better specs than the 737 MAX 10 as the former was designed when Airbus thought it was going to compete with the NMA. 737 MAX 10 tries to be a cheaper alternative to A321XLR, but in trying to be a cheaper alternative to a cheaper alternative, Boeing lost the plot.