There were plenty of rumblings about Boeing's poor quality control after the MCAS issues. Didn't seem to change much. But then again, maybe this is the straw that breaks the camel's back in terms of PR.
The last 757 flew away from Boeing in 2004. It's surely the case that the landing gear issue that happened today has little or nothing to do with Boeing's quality control and everything to do with airline maintenance actions/responsibility.
Maybe different problem here: while MCAS was an engineering problem, door was an assembly problem, here it would more likely be a maintenance problem (757s have been built years ago), which is on the airline or not directly Boeing?