The answer to 'why is my carpet grimy' is that carpets can become grimy and dirty over time due to a combination of factors, including regular foot traffic, spills, and the buildup of dust, dirt, and other debris. Symptoms of a grimy carpet include a dull, discolored appearance, a rough or sticky texture, and an unpleasant odor.
Some common causes of a grimy carpet include not vacuuming frequently enough, not cleaning up spills and stains right away, and not having the carpet professionally cleaned on a regular basis. In some cases, the carpet may also be made of lower-quality materials that are more prone to trapping dirt and grime.