Physicists (and most scientists) are generally of the belief that we're well on the way to having discovered a great portion of all that there is to discover. (You know, Stephen Hawking's idea that we'll have the Theory of Everything in just a few short years.) I personally suspect the opposite - that we've only barely touched on that which there remains to discover. And what we do discover will likely be far beyond the realm of most of our current imagination (just like relativity was, quantum mechanics was, etc. etc.). That bodes well for humanity, which has a deep need to explore and discover and reflect.
How many times does each generation that feels that way need to be proven wrong before we get the idea . . . that we don't know near as much as we think we do; that reality is enormously more complex and infinite than we've been able to yet even wrap our minds around?