The mechanism of making it a for-profit product for the blind people who can pay for it, as opposed as giving it at cost, or even better, having it treated as a basic right of blind people, built and provided by a welfare state to any of them that need it for free.

How is selling products at a profit harmful? If the only reason is that you could provide it for "free" (*insert no free lunch*), then there's no actual harm. No one is entitled to labor/property of others.

On the contrary, however, a welfare state actively rellies on harm (through ~steali~, I mean taxes) to provide said "free" goods.