Several companies making game consoles have done it repeatedly. Phone companies do it. People were actually buying dedicated, word processors for a while despite existence of MS Word & Internet. There's devices that only let you read books. There was one, popular computer that could only play about 5GB of music.
Seeing the patterns connecting them all? That it will be a niche market to begin with doesn't mean there's no market or it's not worthwhile.
Here's one for you given success of gaming and entertainment products: a all-in-one computer combining rapid iteration, memory safety, efficiency, and HW acceleration for common things (esp graphics); a Python or BASIC (eg DarkBASIC) designed for gaming w/ libraries for common features; a port of a game creator program plus examples & artwork to draw on; tutorials a la Realm of Racket or Land of LISP that teach you the language with successive building of game modules with increasing complexity or knowledge required; ability to live patch & debug a la LISP the games with failure isolation so no lost work or long times between runs.
Think people would buy it? Especially people new to programming who would find C++, Java, web stacks, and so on daunting with low-reward steps in the learning process? Could such a HW/SW combination be a 180 for them in motivation and learning?