This is the reason I am not too fond of many magic items in 5E. In 3E magic items were assumed, and if you didn't have them, you'd not perform as well as expected. In 5E, the opposite is the base assumption. If you have no or few magic items you are on the standard power curve, if you have loads of item (which my players have in my current game) you'll be beyond the curve. This means that when I run ready-made scenarios, my players have to be about two levels lower than the expected level in order for the game to be exiting.