I don't know if that's universally true anymore. Hardcore folk will buy it all, but those semi interested in gaming may not need a handheld or console especially if they already have a tablet, which millions will. I look at articles like this:
http://www.appleinsider.com/articles/12/06/27/epics_infinity_blade_for_ios_more_profitable_than_gears_of_war.html
...which tells me that not only is there an underserved market namely tablet owners craving better games, but also that it's possible to make good cash in that market with far less risk than traditional games. I think it's too tasty of a market to ignore, and a standard x86 tablet will be impossible to not target by publishers and developers. Like I stated elsewhere I figure devs will make games compatible on as many platforms as they can to minimize risk so I'm assuming we'll see lots of software for x86 tablets because it's already similar to the pc platform so costs to port games over are minimal. I already think handhelds are dead because of phones, and tablets will be the final nails in their coffin. Now I'm curious how many will pass on spending another $400 on a console and just stick to their pc/tablet instead. Mind you I'm secretly hoping Microsoft goes x86 on their next console as well and makes the apps cross compatible, so that I buy an app once on their app store and I can use it on my pc, tablet and console.
Yes its the most profitable game the company has ever made in terms of many years invested versus revenue. Its however not the most profitable game ever made.
Just because they can take an already made game and throw in textures from past games and get people to buy it doesn't mean its the future of gaming.
Tablets will never work right for games like skyrim or gears of war and if you do add a control scheme why would you play on a small 10 inch screen when you can do the same thing but use a 60 inch screen.
All this talk of tablets reminds me of the talk of netbooks and we all saw how that went. Its a new industry and people want to show off their new expensive toys but outside of a few genres i don't see the gaming boon lasting and for every angry birds , infinty blade and so on there are hundreds of other games that make no money . Not to mention that its very fickle and the boon can switch in a second where at one point its words with friends and then its draw something and then its where's my water and sometimes the fads last a week and sometimes a month.