Oh, yes. There's always a better lens, faster, sharper, quicker focus. Then you need a macro for closeup and a 600mm zoom for shooting wildlife. And if you are a serious birder you need some top of the line prime lenses. To be honest though, if you want National Geographic quality wildlife photos there is no substitute for top quality gear. If you are shooting snapshots of the family gathering or just stuff you see when you're out on a walk, it's more about light and composition than it is about gear. You can shoot very nice family shots with a smartphone.
But the same goes for most hobbies. The marketers are busy promoting the NEED to have their gear and people are lining up to pay big bucks for it. It's the American way.