Re: Background
Because that would be, and I put it mildly, a Fucking Stupid Design.
Agreed. Unfortunately, as the 737 MAX is not counted as a new aircraft, but merely a modification of an existing airframe, it relies on "grandfather" rights and did not have to go through a CoA renewal.
EDIT: Link to Airworthiness Directive released after LionAir incident https://ad.easa.europa.eu/blob/2018-23-51_FR_Correction.pdf/AD_US-2018-23-51_1 (PDF)