Would it be possible to calculate the maximum theoretical value of bitcoins by dividing the world gdp by the maximum number of bitcoins, if so then i am going to have the best retirement ever! 
1st u must have a theory of Bitcoin. To have a theory u must have (an) axiom(s).
If u say, for example, that in the future Bitcoin will replace all other mediums of exchange (axiom #1) u can build a theory and calculate the max value. Unfortunately, axiom #1 looks untenable, coz we all see that Bitcoin is becoming a tool for wealth preservation. In this case it can't be a medium of exchange, so we can't build our theory using axiom #1.
Can u offer any other axiom(s)?