Sad to say, but a lot of them do.
The size of the company actually doing the fabrication is getting smaller and smaller. That means the organization doing the actual work has a smaller staff to support the manufacturing effort.
Large organizations can afford to have a large support infrastructure. The small lean manufacturer has fewer people wearing more hats whether they are qualified to wear the hat and take on that responsibility or not. Many large manufacturers use GE as their business model: subcontract as much as possible to whoever submits the lowest price. If that means going offshore, all the better. They may not be able to read the drawings or speak the same language, but what the hey, their's is the lowest price.
My experince has been that many individuals assigned the role of the "welding engineer" are ill prepared for the roll or the responsibility. In many small companies the inspector or the QC manager may be the individual with the strongest back ground in welding.
Am I advocating for the inspector or the QC manager to be the "welding engineer?" No, but he/he may be the most qualified in a lean manufacturing setting.
Best regards - Al