For me the really interesting part of that is to where the price would go in case the bitcoin market alone would try to absorb some trillions of extra money. After all, it wouldn't simply increase the market cap by those trillions. It would be realized through a much smaller number of bitcoins. Thus, the price of bitcoin wouldn't just go up by 5tn / 21m = an extra 240k $ / BTC. Maybe there's just 4 or 5 million BTC on the market, so it would rather mean an increase by 1m $ / BTC.
Does anyone know a model for that or has the figures on how many BTC are actually available for trading?