I partially agree. It's not feasible to expect the patent examiner to reduce a technology to practice, primarily because a lot of physical technology requires very expensive equipment and some skill to master (chemical vapor deposition chambers for thin films for instance). The ownus should be on the applicant. However, it is certainly feasible for an inventor to demonstrate a working prototype for each claim. Based on the number of rediculous awarded patents I've reviewed over the years, I imagine simply requiring demonstration will probably reduce the number of patent applications by 90%.