That has almost nothing to do with a universal console. Even if the console makers outsourced manufacturing to other companies to be made to their specs. The specs would still be different between the makers and it would still cost the "same", if not more as if they made it themselves as these companies have no wish to subsidize the hardware.
A true universal console would be like a DVD player where everyone agrees to a set of specs and outside manufactures make the hardware, who then sell this at a profit. The big three would become what we have now with the movie studios and everyone would become "third party". As I stated earlier, it would be unacceptable and currently technologically impossible.
It doesn't seem to, but it easily grows into one standard of playing capability. If hardware becomes too expensive for a company to make money by selling the hardware at a loss, using the razor and blade model, then the concepts, abilities, and construction of said hardware will be licensed out to other manufacturers, right?
Well, what happens to the other guys, since we've got three big hardware manufacturers in the game now, and one is licensing things, how do they compete? They can either create cheaper hardware or follow the same suit as the first hardware maker, who licensed out the manufacturing. The former is possible, but unlikely, since the manufacturer would be better off not even creating a new console unless they've got something new to market it with, and feasible options for innovation tend to be mimicked and duplicated on a faster basis as time goes by. Don't forget, with an open platform, manufacturers could easily match any control-based input available on a "less powerful" console, too.
That would mean that the other console manufacturers would likely have to resort to what the first one chose to do -- License out the hardware to other manufacturers. Once we reach this point, we have a format war, like HD-DVDs and Blu Rays, all over again, but with games. From there, it'll be in the publisher's hands: Whichever platform they choose to produce the most content, and provide the most AAA content on will be the winner. Because the platforms are licensed out, manufacturers won't wont to compete with their own product lines, they'll all gain contracts with the "best" platform, and eliminate/neglect to renew their contracts with the other platform makers, and we'll have a single platform.
The good news? To continue licensing out their platform to the big electronics manufacturers, this single platform would have to be more open. You wouldn't want to lose a brand-name manufacturer because they get upset that you wouldn't allow a specific type of content to be created, would you? Neither would anyone else. So in the end, it's likely that the consumer would benefit from this, content-wise.