Actually 18-55mm and 55-250mm or equivalent lens combination like 18-55mm and 55-200mm from Nikon are very good entry level lenses for entry level DSLR cameras. There are good reasons why such lens combination is so popular.
First of all, the lenses are cheap, very cheap. Many consumers think of it a truly good deal.
Second, 18-55mm plus 55-250mm satisfy the most often used focal length, approximately from 18mm to 200mm. Therefore, the combination is good enough for beginners. I believe most users will keep using the kit lenses until the day, as my friend Eric who needed answer for his problem with the lenses.
Eric got his Canon Rebel T3i (600D) 2 years before. The camera came together with with Canon 18-55mm and 55-250mm kit lenses. He was happy with the camera and lenses in the beginning. However he became “unhappy” with aperture range of the lenses for a while. He does more indoor shooting where flash using may offend other people. He used high ISO setting but disappointed with image quality. He considered to purchase a new lens with very limit budget but got no idea what to buy.
I recommended him the Canon 50mm f1.8 for its outstanding coast performance. Eric agreed the lens would be a good choice. But he got new concern soon, carrying three lenses could be really headache for lens change during shooting. He realized the disadvantage of the lens set of 18-55mm plus 55-250mm.
I suggested him to replace the two lenses with one Canon 18-200mm and add on a Canon 50mm f1.8 for indoor use. Eric was happy with this idea and considered to trade in his lenses in a local camera store for the replacement.