MAX happened because the logical change (tweak the body / landing gear of the plane to accomodate the larger engine) would've been too onerous because of the FAA rules, so they fixed it in a stupid way that complied with the FAA rules.
The airlines were also at least partly at fault in the Boeing 737 MAX debacle. They specifically asked Boeing for an airplane with flight characteristics identical to existing 737NG models so that their pilots wouldn't need new type certification, which is why Boeing came up with MCAS as a flawed solution. Boeing and the FAA should have pushed back on that, and found the flaws earlier, but none of that would have happened if airlines hasn't tried to cheap out.
MAX was FAA's fault as much as it was Boeing's.