I can see the appeal of that. It also makes you less exposed to changes in window dressing and to political changes.
..and this is the other reason.
Sure, but it's also bad for the world that "market signals" are encouraging engineers to use bad languages for reasons having nothing to do with productivity. We know the real reason why there's so much Java in the software world: middle managers want headcount (they'd rather manage a team of 50 mediocrities than 5 elite engineers doing just enough work) and Java is such a low-productivity language that it forces teams to be big if anything is to be accomplished.
If an engineer who'd be nothing special in the Haskell community can take home $400k per year slinging Java, then what is a half-decent Haskell engineer (who, most likely, makes a lot less than $400k) really worth? $700k? $3 million?