Earlier quoted context omitted.
We're very much incentivised by earning a living, but given that journals either pay us nothing or charge us for publication it's not particularly relevant to this discussion. You're right that volume of pubs and cites is the important metric, and piracy helps the latter without really affecting the former. Governments and other major research funders are indeed beginning to do what you recommend and mandate various…
Whereas a lot of OA options exist, they are quite scattered. Some universities have preprint servers that are more or less maintained, with varying up times. There are multiple open access options you have to pay for, if your grant or institution has funding for it. You usually have to apply, and spend countless hours getting permission to spend the money, fill in forms, etc. It's all just too complicated. Academics…
The deposit problem is, as you say, a lot knottier. I personally suspect a linked network of institutional repositories with a twelve month embargo may end up as the end state of the current process, which I don't think is good enough.
Sci-hub provides a sociotechnical means of doing differently, and that itself justifies its existence, I think.