Dallen, well if God really did use the 7 day system to help people understand (not that I think it does), you'd think he'd interven now - like he supposebly did very often many years ago in the Bible - and let everyone know what he really meant.
That's what people would think, however, I think god would have more to worry about than to come down and say, "Hold it! I didn't create the world in 7 days, now you understand millions, and billions, that's how long I created. Well see ya guys later, I'ma gonna hang out at my crib for the next few million years. You guys take care. TTYL and BFF!"
That brings the next question about "god" concept is that people want to say, "Well if there is a god, then how come he doesn't do this, or that?" And that's easy to say, because god wouldn't do anything at all. I found that a lot of times if you've been reading these forums at all.
And just FYI, god didn't intervene a lot in the new testament. In the old testament, and the new one, Jesus came down, and supposedly now god no longer needs to come down because all your sins are forgiven. In the old testament, in order to talk to god, you were suppose to sacrifice an offering (usually a lamb) and god would come down and be like, "You called?" But now that Jesus came and went, it allowed us to be forgiven and god no longer needs to come down. In the old testament, god had connection with people, up until the new one. The only time god came down and directly talked to someone is for people who were recruited by the disciples to spread the word. Their objective has been fulfilled, and god no longer needs to directly come down. If there is a god, and you died today, and he would say to you, "But why did you need me to talk to you when you already know what I told you?" Because you do know about god, back then, people didn't so god need to tell people to spread the words.