In some ways, there are now a lot of devices which can play games like Tablets, Smartphones, cellphones, MP3 video players like the iPod Touch or Android Video players, laptops, ultrabooks, netbooks, PC, TV boxes with built-in games, calculators, hand held, consoles, DVD players, and a bunch of other devices.
I think there are now more choices for what people can use to play games, so their not stuck only using one device to play games unless they choose to only use one device to play games.
I think having more devices which can play games means there will be more competition, so it can be a good thing since companies need competition from other companies to motivate them to work harder to have better games then their competition at the same or cheaper prices.
I was happy with two consoles, but you know the major problem about more gaming devices?
no time to play them all.
unless I somehow return to my grade-high school days or some how retire very early, there is no way I can get around to all the consoles and their games. Not to mention the money it takes to buy them all, and that crap isn't getting any cheaper.
But, without competition from other devices, games, consoles, online accounts like Xbox live Gold, PSN Paid account, and the accessories for consoles might be even more expensive, or take longer to drop in price because of no competition from cheaper alternatives like the Nintendo Wii, Xbox 360 Arcade 4GB, and other devices which can play games like Tablets, SmartPhone, Google Android devices, Mac, Linux, and PC.
I just buy the games I want to play used, and play when I have the time, so it does not really affect me since I still have a few games I haven't completed yet.
But, competition helps keep the prices for buyers from being too expensive at the store since the buyer have a choice in buying a Nintendo Wii which is cheaper, and have some better games and controller for people who like the Wiimote instead of being stuck with the PS3, Xbox 360, or other gaming devices which they might not want compared to owning the Wii which they love.
If the Xbox 360 did not exist, the Wii might cost a little bit more money since the only alternative is the PS3 which was very expensive when it launch.
Some game makers also borrow ideas from their competition like Just Dance might have borrowed some ideas from Dance Dance Revolution, Pump it Up, Boogie, Singstar, Guitar Hero and improve their ideas in Just Dance to make it more fun for the player.
http://www.youtube.com/watch?v=4aaswYX_JTo
Saints Row also borrowed some ideas from Grand Theft Auto, so people who do not like GTA very much might like Saints Row better because it is different, but have the same theme.