I think the big players are basing their projections on taking over a majority of the market. The only way they are going to turn a profit is if they scale to something larger than would be possible for multiple players.
Also, there is the idea that the first company to be able to successfully turn their on technology toward self-improvement is going to get such a quick boost that no one else can catch up before they take over the market.
But I could be wrong. Do you see a stable situation with multiple players at the scale they are betting on achieving?