It's well known the XBox 360's capabilities is severely holding back multi-platform developers.
The current situation with the 360 I see as a love and hate thing.
If the XBox 360 stays on the market for many more years, the positive aspect is that there's a bigger 360/PS3/PC installbase for multi-platform game companies to take advantage of. Allowing for bigger multi-platform game budgets.
If the XBox 360 is discontinued by next year, that would also be positive as PC/PS3 games development can gain a lot from this from a technical perspective.
As time goes on and the PS3 installbase increases, scenario 2 gets ever more interesting and relevant.







