Since the M3 model says US$75 trillion exists in the world, with 21 million bitcoins, that is around US$3,500,000
There is no way that bitcoin could get to that level without fractional reserve banking. Assuming a 1:10 ratio, you should cut your value by a factor of 10.
BTC value is tied to gwp and what % of people use it as the Bitcoin Algorithm proves
You can already estimate the percentage using the ratio of the amount of currency in the world today over the current GWP. However, the velocity is likely to be higher so the percentage is likely to be lower.
Not going to happen. As bitcoin gets more expensive, altcoins will provide the supply needed for the utility of bitcoin (doing business) which will reduce the demand and thus price of bitcoin.
The value of a bitcoin has not limited its adoption so far.
Newcomers to crypto-currency aren't going to want to be part of a system where a select few have incredible wealth, hence why they will opt for altcoins instead of bitcoin.
People already accept a system in which a select few own nearly all of the wealth in the world. That will not be a factor.