I wouldn't call that "maintenance." It's a repair.
I keep getting the impression that one of the reasons we are seeing so many flaws in Boeing aircraft is that EVERYTHING on them is designed so close to the edge of serviceability and built with less than stellar attention to detail as means to meet competing mandates and directives, from "climate" to fuel economy, to DEI hires for assembly technicians...
There are only so many straws that camel can take.
Based on what evidence? How many Boeing aircraft today are flying safely, and for decades!