I am pretty sure it will take much more than 4 races before he can be given the crown. This is because of the way the current results stand.
Assume as you say, Michael wins the next 4 races - he will be 110 pts after 12 races. Now take the worst case scenario (for Michael) - assume Barrichello comes 2nd in all four - he will be 86 pts at end of the 12 races.
As there are 6 GPs left after this ... meaning 60 points on table, Barrichello could still overtake Michael to the crown if Michael fails to score/scores poorly and Barrichello wins them all.
FIA will only award championship only if it is mathematically impossible for someone else to win the championship. So it can't happen after 4 more races.
Therefore it is more likely that despite Michael's dominance this year he is likely to win it after say 14 races assuming he continues his stellar performance.
The difference between 2002 where he won it in France (after 11 GPs) and now is that in 2002, Michael was on 70 points after 8 races (Montreal) while his nearest competitor Montoya was on 27. He had a massive lead which helped him close the championship early.
This year he has a lead of only 16 pts over Barrichello despite winning 7/8 races. Barrichello has driven well and Michael missed out scoring at Monaco. Also the current points scoring system mean that wins make less of difference than in 2002.
I personally wish that he can close the deal in Spa or Monza