This is an interesting topic, and I think David is right that integrating PDM is a bigger technical undertaking than it appears. However, I believe the lack of interest in a built-in product actually has more to do with political constraints than it does technical ones. You could ask the same question about CRM. Why do all these CRM companies exist selling separate software when operating CRM separately creates such a mess with your data? I think the answer is just that it is very difficult in many organizations to get everybody coordinated and playing on the same page. The sales people want CRM, they want it now, and they don't want to have to talk to or coordinate with the people in accounting to get it implemented, so they implement a separate system. I once did consulting on implementation for an integrated quality assurance system on an ERP package, and discovered surprisingly stiff resistance from QA department managers to implement that. They had moved heaven and Earth to get ISO certified and had no interest in re-implementing all that again just so they could be on the same database as the accountants. I suspect the same politics might exist with PDM.
In any case if you think there is an opportunity here we do have methodologies for building extensions on to xTuple for people like yourself who have domain expertise and believe there is value added by integrating that seamlessly into our ERP system. The next question, then, is who will either do or underwrite the development work, sell and implement the product? These are important questions that require substantial financial and time commitments from some party. If you are interested in committing time or money to getting that kind of work done, we're certainly open to having a conversation on how to coordinate with you on that.
If you are interested in learning more about how our extension methodologies work check out this page:
I look forward to hearing more about your ideas. The idea of integrating PDM with ERP does seem logical to me.
I laughed when I saw your implementation stream that included Copics. I too was involved in a company a while back that went from Macola to Copics, Copics to Oracle, and Oracle to what is today an Infor product, all the while because the company kept changing hands. It's amazing how much effort is expended by people to accommodate these acquisition transactions, with pretty much no value add at the end of the day.