Also I wouldn't be surprised if part of the reason for not making Sins 2 straight away is to let the technology catch up a bit to their plans. Once everyone has 64 bit machines with over 4 GB of ram and who knows what else, they'll be able to do a lot more than they could if they were to start development right now.
Well, 64 bits have start in 1985 with cray computer and Unico ( unix x64 )... at a large scale, console have move to 64 bit before 2000 ( nintendo 64, PS2, etc )... move on computer was more slow first because hardware but mainly due to the OS... linux x64 was ready in 2001 but for a windows version, it have only happen in 2005 with window xp pro...
2005 is the purchase date of my actual computer... 2 processor x64 quad core, 16 gb ram ... so, it is fare to be new... problem is again the OS... xp pro x64 was released in 2005 but it was a pro version... lot of people have remain with the usual xp 32 bit shipped with the computer... later, Vista was a flop... Only recently ( a few year ), with Win7 being x64 capable from the Home version have allow people to fully use the power of their old hardware...
And of course, game developper cannot make a x64 game without a enough large amount of people using a 64 bit OS... as today ( january 2012 ), it seem that almost 40% of people are always using a 32 bits OS ( xp, vista, win 7 )... xhexk at http://store.steampowered.com/hwsurvey, click "OS version"...
At this rate, hardware will move to 128 bits before everybody have upgrade to x64 !!!