If you increase your skill/knowledge that doesn't hinder your ability to use PeopleSoft/SharePoint. It certainly expands your options. While you can get a good salary using those technologies, eventually they will be obsolete. When that happens, we'll start to see news stories posted on some future-HN about how older IT workers are being passed up for younger, fresher IT workers and how it is a biased industry. When in fact, its just a group of people who decided that sitting in their comfort zone doing their day-to-day was good enough and when it was time to move on, they couldn't find any other jobs that fit their particular niche they'd had for the last decade(s).