Design change to increase passenger capacity and not have to design a new plane, which would have required all their pilots to be retrained on a new plane design.
So, they threw these huge jet engines which are too large(by diameter) to fit under the wing. Solution was to move them forward. That changed weight balance and required software to “fly” the out of balance aircraft so it didn’t crash. Well oops it did a few times!
No modern passenger airliners have engines directly under their wings. Take a look at the Airbus A320’s and the previous generation 737 NG’s engine placement. They are all forward of the wings.
With the statement you made, I doubt you would be able to tell exactly how much further forward the LEAP engines on the MAX are than the CFM-56 engines on the NG.
MCAS wasn’t in response to weight distribution of the larger engines being moved forward. Think about it. Shifting weight further forward of the center of lift would require trimming the nose up. The MCAS only trims the nose down. So you may wish to work on your logic a bit.
Also, the larger fan diameter is for increased efficiency, not for more passenger capacity. Turbofan diameters have increased drastically over the decades. The original low bypass turbofans on the 737-100/200 look like cigars and actually did fit under the wings.
That generation of 737 (“Jurassic”) was supplanted by the 737-300/400/500 “Classic” series with the high bypass CFM-56 turbofans mounted ahead of the wings… in 1984. And then Airbus put those same engines in the same place a few years later on their new A320 family. That’s where the engines go now, even for the big jets like 777’s and A350’s.