I don't know why electricity usage is such an issue . No doubt , the mining consumption is way too much . But everyday people come out with alternatives to deal with the problem . Why not use these alternatives and finish the problem for once and for all ? Using solar energy can stimulate and make the process more cost effective and efficient .
This leaves me to the third point. It is not possible, by definition, for everyone to "exit" the bitcoin. Yes, one can sell it, but that just means somebody else has it now. Or, a whole group, like "smart traders" can sell it, but, when looking at all the people in total, there is never any "leaving bitcoin" happening. The same is true for USDT, and surelly that 700 million USDT played a huge part in this rise from 1k to 16k for Bitcoin.
The "smart traders" will always stay in the market . That is true that there is no term like "exit" bitcoin . They just look out for the best opportunities , ways and customers to sell their coins and get the best profit out of it . The players never leave the field .