No, you can't take an early stage, pre-revenue company public. It takes ~7yrs plus or minus to scale a company from nothing to large enough to list on public markets, which is what VCs are for.
Sure, that's how it is now, but it definitely hasn't always been that way. The original public companies definitely were "early stage, pre-revenue," though you can argue that those were long enough ago to be irrelevant.
Intel's IPO was 2 years after the company was formed.