> Boeing wanted to do the same. Their design didn't accommodate the bigger, more efficient engines they wanted. So they created a workaround.

Note that Boeing had this problem ever since the 737 Classic (the second generation 737) was introduced, hence the non-circular engine inlets they've had for decades. This cost them efficiency, at the benefit of maintaining commonality with all its advantages.

Note that last I heard Airbus was planning a clean-sheet redesign for the A320neo's successor, targeting an early 2030s introduction into service. If you allow me to speculate for a moment, Airbus is in an interesting position now having the A220 in its family: it could easily stretch the A220 to be comparable in capacity to the A320, leaving an A320 family replacement to focus on the A321 and the smaller midsize market.