I'll say the same thing about the 3070 that I will say about most video games.
Wait for all the independent reviews, never preorder anything, and falling victim to FOMO hype is not good justification for a big purchase. It's not a good idea to order a graphics card a few weeks before a major graphics card launch (and the day after announcement, really). We don't know what Big Navi will be, but we do know that it was enough to make Nvidia price their cards (relatively) aggressively (compared to their own bloated prices).
Yes $500 seems inexpensive... but only because it is being compared to a card that was universally panned for being overpriced - even 2 years ago when it was brand new and before people realized that nearly no games were going to end up supporting RTX.
Another reason to wait and see for Big Navi to be released/tested: games are always going to target consoles over PC, so future games with ray tracing are going to be optimized for AMD's method first, and Nvidia's method "maybe, if they pay us".