I dont see the justification when a new console costs just as much as the equivalent graphics card needed for new titles. I'm sure this will be the case for the X-Box 2 (or whatever they call it). Probably even more so if the gfx arch is kick-ass. I can see the desire for having a single appliance that does it all, but those days are rapidly coming to an end...
PC (Mac) games are slowly dying IMO -- There just isn't a compelling reason to buy a game for a home computer when a console can host the same titles with essentially plug and play ease of use and arguably better production values in some cases (which, admittedly, is wierd, since most of them use the same assets for the port.. but I guess it has to do with supporting all the various hw combinations... oh well). Plus the software house can make money on the console version much easier than the PC version for one big reason (that I list below).
I think people usually want home computer games for the following three reasons:
* They want bleeding edge gfx titles. Usually predictable boring FPSs with awesome gfx engines that dont matter for playability. What's most popular FPS of late? Halo on an xbox...now Halo2.. not even a cutting edge engine really... just a good game with great production values. I think Doom3 and the subsequent disappointment post release in indicative for the future of those titles and pretty much the death knell of the gfx card/fps race. I mean, it wasn't even that pretty compared to the last generation.
* Simulation. You need processor and RAM that the consoles dont have. Not many people are truly hardcore about their sims, most want a good game. It's hard to sell a completely hardcore sim. Arguably, Colin McRae and Grand Turismo are the best driving sim games you can get right now.. both are available on consoles -- one is exclusive to a console. But most of the good stuff is home computer only, making this reason really the only real justification IMO for wanting a home computer game.
* Cheap. The unspoken reason -- and I honestly believe the real motivating reason people whine about not having a home computer port of a particular game -- you dont need a modchip to dload the cracked version of the game. Obviously, this alone puts PC's *way* far back in relation to consoles as far as the market is concerned.