Nintendo did it great in 1983, then it was Sony with the Playstation in 1994. After that Microsoft started with the XBOX.

New players entered the console maket and made good sales or conquer the market.

Now entering requires a lot more to be succesfull, a network, multiplayer, the cloud, streaming and so on. 

What new player can be able to enter the market?

Steam is coming and maybe google can do the trick if it wants?

what do you think?

I'm not sure if it's even viable to enter the market in a traditional way. A new player in the market would have to be willing to take a losses to establish a strong footing.

I see a new player entering only by buying into an existing console. XBox seems like the prime candidate to get sold, and Google or Facebook as best contenders to purchase it.

Apple. They win by default.

They already tried and failed horribly.

Eh. You think they will? I wouldn't say so.

Nobody in the traditional sense. Android is the future!!! =P

I think that the more consoles there are, the more saturated and unhealthy the market will be. With three mayor current gen consoles and two still active last gen consoles, plus PC, two big handhelds, Mac iOS, mobile and tablet, miniconsoles like the Ouiya... people usually pick one or two to fully support (then there's the people who own all of the consoles, but I don't know if they have any money left to eat lol). Plus most developers only create for a couple of consoles, because developing costs are expensive.

But if I had to pick a new competitor, it would be Google or Apple. Both have already experience in games, and are big enough to keep advertisement and game support for its systems.

Apple, obviously.

I doubt any major company that could has any desire to enter the console market. Apple showed how much easy money can make on their apps and games with minimal effort. Why Googly followed that path instead of competitive region. Given the losses Sega, Sony, Microsoft and even now Nintendo have had to endure the market looks saturated in terms of dedicated video game consoles.