There's some nonsense in this thread.
No, the UMC is not a short life disposable item. Mine has been my permanent daily at home charger for over 9 years.
Doing a search, perhaps " 2-3 years is not uncommon for frequent use" was a bit severe, but here are some citations.
But you didn't search for failures of the wall connectors, did you? That's the point. Many of the wall connectors had failures running at their maximum 80A too, the same as the mobile connectors did at 40A.
All of these Level2 chargers are very simple. Just a relay and a circuit board. The circuit should last forever. The relay could be subject to wear from arcing with frequent use but not likely.
These should last a long time. I have several Level2 chargers which I have had for up to 8 years. Never any kind of failure.
I think it's usually not arcing, but heat cycling. The farther that difference is from the on/off conditions of hot and cold, the more expansion and contraction of the metals there is. That can make solder joints brittle and eventually crack. Things can be built in a way to try to compensate for that with thicker connections, but some products do that better than others.
That's also why there is a very strong correlation among vastly improved lifetimes of wall and mobile connectors when they are run a some lower level amps below their official maximum rating they are supposedly built for. It keeps them cooler and has less degrees of that daily temperature movement, so makes less materials stress, which usually makes them last longer.
I think there also might be some cases of misleading correlation that makes people accuse mobile connectors. It's like noting that increased ice cream sales correlates with higher rates of shark attacks. That's a true statistic, but the ice cream isn't causing the sharks to bite people. The mobile connectors are usually lower power devices, so they are more often being maxed out. Whereas people frequently were using an 80A max wall connector at 40 or 48A, which is already a lowered rate than it's built for, so it is that cooler functioning I was talking about.