Not all rights, simply exclusivity rights. NFL 2kx with full NFL rosters would suddenly be possible, but Madden would exist

maybe sega will make a remarkable comeback, who knows?

But, the micro was just another gba revision. I don't know how many units total GBA's sold, but there were only 2 versions of the n-gage, which sold about 3 million (to date, it's got a following in india)

Not a single one of them.

Entering the hardware market is simply too cost prohibitive now. MS got the last seat at the table.

To be successful would require a sizable internal studio and lots of 3rd party and retail support.

1. Getting a sizable internal studio would be very tough short of buying out a bunch of studios and those studios are coming with huge price tags.

2. 3rd parties are already spread incredibly thin providing software for more platforms at once than ever before (2 Nintendo, 3 Sony, 1 MS, PC and Mobile = 8). They will be highly reluctant to spread themselves even further to support an unknown entry.

3. Retailers have limited shelf space which to support those 10 aforementioned platforms. Try asking them to make room for a 4th major home console and they'll laugh you out on your ass.

True. Then again, that's not really what this thread is about.
In the scenario above Sony, Nintendo and Microsoft leaves room for another competitor by not launching an 8th gen console in the next years to come. Thus the incentive for releasing a 4th console increases each and every year.

3. Again not an issue in the scenario. In 6-10 years bandwith will eventually run some "videogame shelf space retailers" out of business. Distribution is not a problem when it comes to meeting demand. Shelf space is not a bottleneck when there are profits to be made . In the end flexible retailers always have to adjust (not the other way around).

I think there is potential for someone much smaller to come in to the console market.

Such as GPX2...and make it open source and see what people port. As well as get some internal people to make games for it...

As far as the giant companies are concerned...you know you are in trouble when Sony and Microsoft are fighting for scraps.

I can't see anyone entering the home console market but I can see someone perhaps going for handheld. Apple is already trying to say they are competing in the handheld market but they are pretty much just raking in money from games on the ipod touch/iphone.

I have a hard time seeing a 4th contender in the console market. Whomever in last place will most likely leave the market. I just dont think the industry can support 4 consoles.

There won't be a new one, but if Sega does come back oh this will be the best day ever unless Skies of Arcadia gets a equal...

Without a doubt this will be done.  Great example with the GP2x.

Everyone who says it won't happen, just think for a moment:

The old barriers of monster processors, big graphics cards, huge brand names are gone.  People will buy and play anything that's fun, including games from the 80's.  One of this generation's best games was made by two people.

Wii was originally designed to be $99 and still sold for profit.  Imagine a company that actually picks up on Miyamoto's original vision.