Nintendo also takes a 30% cut, although it used to be 35% for WiiWare games. This does NOT include the cost of acquiring development hardware, which usually sets you back $1000 at most. 30% is actually the industry standard; Steam takes 30% and Epic Games takes 30% for smaller titles.
Regarding your comment on captive platforms, I think there's a bit of a difference between a home console and a smartphone. A home console is considered a luxury item, while a smartphone has quickly become a necessity in today's connected world.
For home consoles, market competition is fierce. Not only is there Nintendo, Sony, and Microsoft, but there's also the PC gaming market, which includes devices in a variety of form factors. There's also multiple storefronts. You can buy console games from physical stores, in which case physical retailers take a cut, purchase Steam keys from other vendors, trade physical games, etc. In summary, there's a lot of ways to acquire your games.
In contrast, smartphones are seen as a necessity by many, and there are really only two options: Android or iOS. Each has a dedicated storefront that captures almost their entire user base. This gives Apple and Google a LOT of power over what people can run on their devices, and it practically gives them a guaranteed source of income. I can see why people's attitudes are different towards the Apple/Google duopoly, and that few people are complaining about Nintendo's monopoly on the eShop.