The problem isn't the porting devs. or publishers.
Your gripe should be with Nintendo...........I heard Nintendo charges 3rd party publishers and developers about $15-$20 for these cartridges, which are really just enhanced SD memory cards at this point. And that is just for the 16 GB cartridges.........I hate to see how much they charge for the 32 GB cartridges that Nintendo supposedly has for publishers.
So the $60 3rd party ports is more of a result of Nintendo wanting to soak up more money from the 3rd party devs. than anything else.
That being said......yeah, it inexcusable for the "digital copies" of these 3rd party ports. But then again, Nintendo could also be charging a "Switch tax" as well for even making 3rd party ports available on the eShop.