how to encourage investments into an obvious market

there are millions of humans without one arm and/or leg 

and a robotic prosthetic arm or leg costs 20'000 dollars or more, 

the potential market value of this is enormous, 

the trouble is financing the buyers, but the producers will earn a lot of money, 

it's weird that not every big tech company has research and development of robotic prosthetics, 

almost irresponsible towards the shareholders of big tech companies 

there is no point of big tech companies waiting for government subsidies before they start serious research and development, 

as soon as there are quality products on the market, government subsidies will come because of public opinion