I don't agree and my experience bares that out: You can show your expertise, even when answering the most basic questions. You don't legislate away easy questions as if top-tier experts are just going to start filling the void. Sure, you have to ask great questions. But you also have to consistently provide awesome content with every answer, no matter how simple or mundane. That's how you will gain the respect and recognition of an expert community.
Some of the most highly-respected physicists in the world are teachers; answering Physics 201-level questions from rank-and-file students. Think about it. If you heard a seminar from someone like Einstein or Newton eloquently describing how gravity works when an apple falls to Earth, are you going to say "Nah, that's baby stuff" or do they somehow maintain that go-to source authority when it comes to areas of expertise. Be a great teacher!
In the intervening time between now and when this system is filled with world-class physicists using this site in their daily work… keep in mind that only a small percentage of the content of this site is questions. What you can offer today — right now… with the talent you have right here — are world-class, canonical answers to those questions.
Warning: Boring Anectodote— When I first started using Stack Overflow, I had 25 years of expert programming experience when I asked my first question (link). Without getting too technical, I was asking about, quite literally, one of the most basic concepts of a programming language. Surprisingly, the answer provided some deep, insightful responses I never expected. One was from a Microsoft senior developer on the team that designed the language; The other from someone who literally wrote the book on the subject. Unmatched, expert-level answers to a canonical question; That's the level of response we've come to expect from Stack Overflow.
So when someone asks "why do apples fall down to the earth," provide that world-class, canonical answer which can be improved upon indefinitely. Every time someone searches for an answer to their question, this site should have THE canonical answer on that subject — that, and every subject in physics. When an expert happens across this site, they should say, "Woah! These guys know what they are talking about. This is the site for me!"