From a personal standpoint I really like the idea that I am not an island by myself and if a client needs more people like me or more specialized help, then I can easily refer to a large talent pool of like-minded people who I know can do the job for my client. I like to call myself a generalist who can perform any UX task, but sometimes a client requests an expert with a specific UX skill, like technical communication write or competitive analysis expert. A good example of different UX skills are listed in the following article "The 10 UX Deliverables Top Designers Use". This brings up a completely different set of problems.
What is the true role of UX? Are we just in the deliverables business or producing beautiful artifacts? With the advent of Agile, whether it be Scrum or Kanban we must be mindful to produce deliverables that result in an improved product. We need to have actionable items in every document we produce. If we have a heuristic evaluation, then the output needs to be a bulleted list of items that can be given to the development team to fix in priority order. If we run a usability study on a prototype, then it should be driving a refinement to our proposed design. Then comes the hardest part of our job, in working directly with developers so there is no misunderstanding between our concepts and final product that is shipped to customers to use. This can be done by inserting yourself in the development team to help all along the way to be available to answer questions as they arise. Also, as development tasks are completed, there is a QA task to ensure that the whole product meets the original UX design or improvements proposed along the way from monthly usability studies.
The goal of every UX designer should be a product that matches the mental model of the actual end users and helps improve their life.