For sure, Apple’s switch to PVC-free cables (around 2010 I think?) led to years of cables with poor longevity. (Like the insulation seemingly growing in length over time, causing it to buckle and eventually split open, splintering lengthwise at strain points.) It took a long time for them to find something that works. And even now I’d argue that PVC insulation still holds up better.
The very first generation of lightning plugs was susceptible to the same failure mode that affects many USB-C and HDMI plugs (and nearly all full-size DisplayPort plugs) today: snapping off of the little PCB the connector straddles, if the plug housing is subjected to any force. They quickly changed that to a better design that is well-supported, and that problem vanished. (Both in Apple cables and in authorized third-party cables, since Apple supplies all Lightning plugs for those.)
At some point much later on, they changed the plating of the contacts from gold to rhodium to better resist arcing damage from hot-plugging. A super common failure mode was for arcing to damage the gold plating, and then for moisture and finger oils to provide a path for electrolytic corrosion. (Since the contacts on the lightning plug are completely exposed, it’s very easy for them to become contaminated.) Look at many a well-used lightning plug and you’ll see one contact per side that is corroded while the others are largely intact; that’s the 5V contact.
While I can’t verify it, I assume the 5V pins in the connectors also have more corrosion, due to contaminants transferred from the plugs.
This question never occurred to me before, but I wonder if this a contributing reason to why USB-C was designed with all its contacts recessed, even though it makes the plug a bit fatter.