Why The Boeing 737 MAX 10 Has Such A Long Fuselage

The Boeing 737 MAX 10 is the longest version of the 737 ever built, and will compete directly with the Airbus A321neo. It is expected that the MAX 10 will eventually replace the market that remains from the 757. With a similar capacity to the A321neo, the aircraft will be substantially lighter (2.8 tons lighter), meaning better fuel efficiency and range but has Boeing stretched the 737 MAX 10 too much?