I think that GT5 is a different example, which costs are very difficult to acertain.
Reason I say this is that we can look into what's actually involved in Prologue vs. the full version. Is GT5 just.......More of the same? This is a very important question, as it's critical to 'figuring out' what the GT5 budget is.
On one hand, the GT5P and GT5 Full costs could be shared: GT5P cost very little to make if it was a spinoff of GT5, and all that costed was some simple development time of taking what was ready for GT5 and porting it to a Prologue, or if the full GT5 had a lot of fundemental work that was different.
The likely scenario is that GT5P used a significant amount of assets from GT5 Full, and cost very little to make, so it earned Sony a large amount of profit, to offset whatever massive costs GT5 took to make (I'd think around $50m for GT5 + $5m for Prologue, or a little less).
Back from the dead, I'm afraid.
