How durable are merino base layers in practice?

This is where high-trust community sources sharply diverge from glossy expert reviews. r/CampingGear and r/BuyItForLife threads repeatedly call merino 'far too delicate,' with users reporting holes within a season or two of regular use. The fix, recommended in r/alpinism, is to wear merino under a more durable midlayer rather than as a standalone shirt.