Holy smokes!!!
I would say that looks like symptoms of excessive heat, which is detrimental to magnesium pistons. So you’re probably spot on with dull chains, components packed with crap, and no load high RPM. See the article below.
I suppose one might argue this means it’s not as durable… and if your definition of durability, includes very poor maintenance and improper use…. Then I guess that would be correct.
But simply sticking to the norms of chainsaw use and maintenance is probably all that’s required to get equal service life.
On the same token… these considerations might make a magnesium piston’ed saw less suitable for things like wildlands fire fighters, where an operator might require a saw to push through in a high heat environment, with a dull chain, packed full of all kinds of nasty contaminants.
But that’s a very unique situation.
https://www.highpowermedia.com/Archive/magnesium-as-a-piston-material