Servos are mass produced but still expensive! You're right, but also software is weird. The world is absolutely littered with good computers that other people

Servos are mass produced but still expensive! You're right, but also software is weird. The world is absolutely littered with good computers that other people have already paid for, just waiting to be put to use for your project to expand their capabilities. If every new web app required its own little pocket computer to run, that you had to convince your customers to buy and keep in their home, it would be much less profitable to develop web apps. The world is not littered with idle, high-performance robots waiting around for your motion planning algorithm to kick them into action. That makes it a lot more expensive and a lot less profitable.