You would have to be prepared to drop billions of dollars to get a console to market and expect not to see any profit at least to the next gen and thats if you have been succesful in making head way, Today we have 3 makers with the Wii having enough of a differential from theHD twins to make it work even then Sony has lost billions this gen and got to a stage that some people reported that the Playstation including the PS1 and PS2 's profits had been eaten up by the PS3 and there best case scenario( IE ten years or more of ps3 on the market and all remaining years profitable) is for the PS3 having enough turaround for the PS1/2 &3 combined to be back in the black in some small way and thats not something to smile about.
So i think three is tight and next gen the console makers will factor this three way battle into there strategy far more than last gen. Since there last foray into the market there Ips don't resonate like they once did and there competion software wise have grown plus i don't really think 3rd partys are going to split development resources even further .