From FB comment
There are many factors that affect price. One part is getting things assembled by underpaid and child (illegal) labor. Most discounters have been caught buying their goods from these illegal sweatshops, and they still turn a blind eye to these abuses. The net result is that the quality of the components may not be so bad, but the overall quality may suffer because of quotas, sloppy assembly due to hurrying, or the use of the wrong parts.
Reminds me of long ago when I worked as a test tech. Some boards wouldn’t pass tests, and had very strange problems. Upon closer inspection we found that some of the dozens of diodes were, instead, zener diodes. Someone had put a handful of the Zeners in the bin holding signal diodes. They look the same unless you read the markings with a magnifying glass.