From a consumer perspective, upgrading the number means "the same, simply better and faster". (just like an iphone :)
The truth is probably more complex than that.
From my experience, 4G was much more reliable that 3G has ever been. May be the service providers have improved. But I have the feeling that 4G is a fundamentally different technology from 3G. In that case, is 5G fundamentally different from 4G?