Well, maybe a more appropriately worded bout of questions would be:

"Is it a realistic approach towards success to make a demo and ask for investments?"

"Have any existing successful games been lead to their success by making a demo - in other words, is it even worth trying?"

"How do gaming companies make their first game if they don't get investments - especially if their first game requires millions?"

I guess I just don't understand how gaming companies got there in the first place, making games like World of Warcraft. Blizzard had Warcraft and Starcraft before WoW, but those two were pretty large games, too, and I doubt if they were cheap to develop (though I'm not sure if Warcraft and Warcraft II would also require a large budget).

Blizzard started out under the name "Silicon & Synapse" primarily porting games for Interplay to new platforms, They did however also create a few titles of their own such as The Lost Vikings and Rock N' Roll Racing).

The original Warcraft: Orcs & Humans (released in 1994) Had a rather small budget for its time and reached its huge success in part due to a lack of competition (There really wasn't that many RTS titles on the market at that time, Warcraft(1994) was pretty much the only decent RTS released in the space between westwoods Dune II(1992) and Command & Conquer(1995), both of which had a sci-fi setting rather than a fantasy one) , Warcraft most likely sold far better than it deserved. (It wasn't a bad game, but if it had been released a year or so later it would have completely drowned in the much higher budget Command & Conquer release)

So no, Blizzards first game didn't require millions and they've basically been around for 20 years now growing slowly over time. With a few highly successful titles causing them to grow relativly fast at a few points, they were also extremely lucky with their warcraft release timing. (If they had been forced to compete head on with C&C with a new unknown title they would probably have failed badly, being able to go up against it with a much higher budget sequel (Warcraft 2 was released a bit over a year after the original and had a far bigger budget)