Of course good cross-platform development requires proper abstraction and polymorphic programming to reuse code in the most efficient and effective ways possible. The whole case should be mapping modules across and balancing resources. of course it requires many other things, technical and not. It requires friendly people too who can collaborate to solve problems, a good management team to keep things on track and maintain a highly productive and integrated team, etc. Not sure how well Beth does on such ends, but my guess is they have a proper team of developers who at least know what they are doing (they are a big company after all, and it's probably competitive to get a job there too, although we can't be sure - they may as well be a bunch of too-much-talking not-much-doing sort of people). It also requires at least minimum resources, which is what they claim are lacking on PS3 - at least this is the caramel they've been selling us since day 1.
These are reasonable speculations, although there is a bigger factor at play here. without MONEY nothing can be put to work. without MONEY you can't do sh*t. and MONEY shouldn't drain your profits, unless you are some sort of not-for-profit organisation, which they sure as hell aren't. If they have proper IT and Management teams they should have done proper cost, requirements and if not risk anolyses before even engaging into development. So maybe resources are not the problem. Maybe lack of development skills is not the problem either. maybe what we are faced here is a simple not-worth-it investment, which neither SONY nor Beth are willing to undertake. so i for once don't expect much to be coming my way. maybe something developed a long time ago to at least get a few mouths shut.
oh well, maybe i am totally wrong and they really svck at putting things together, in which case we may get lucky

p.s. this is only regarding DLC. the problems we have on the vanilla game are a different topic, although the two are related. my take is that they could have always released a "lighter" version of the DLC if that's what it takes. again, it comes down to good management and incentive