I agree with you that Nushare market cap can “store” money/value for nushareholders, but disagree on “how”.
Your solution: take value form NBT reserve to NSR via nushare official buyback; and reverse the value flow via selling NSR and reinforce the NBT reserve.
One big problem of this solution is NSR’s volatility, the fact of recent months has demonstrated that we usually have to buyback at high NSR price level and sell NSR at very low price. Losing money mecahnism for Nu! Those NSR sellers at official buyback get rich, and those loyal NSR holders get poor/diluted. When Nu need to sell NSR to help peg, it means Nu need money, and usually peg in danger, in this situation Nu need to sell NSR, this will ruin NSR’s price, have you heared of The Matthew effect?
For unto every one that hath shall be given, and he shall have abundance: but from him that hath not shall be taken even that which he hath.
— Matthew 25:29, King James Version.
If you cannot remove this flaw, Nu has no future.
Psychology involved heavily in share price, you need to build up a mechanism that encourage people to hoard NSR, cherish NSR rather than panic selling on official buyback.
Look at the success of bitcoin, the PoW mechamism makes people cherish BTC.