Short answer is yes, but it would take a long time.
There is no question that the web based gaming market is much hotter than offline / installer based games.
With web browser based games, anyone can signup and play from anywhere, they don't need powerful computers and they can get started right away.
In the evony vs Wow debate, blizzard has built a huge market that will take years to topple. But they aren't increased at a rapid rate - unlike Evony, who are surging ahead in new accounts.
The next few years will be very interesting to see developments in this free browser based MMO niche.
