P(rice)/E(arnings) ratio of 1 would mean it pays for itself in the earnings period.

The earnings period is 1 year.

It would mean making 100% return on investment each year. Being that low is only possible if there's reason to think the business is extremely precarious and unlikely to survive.

P/E 30 means returns of 3.33%, P/E of 20 means 5%. These are sensible numbers given people have other investment opportunities.

P/E of Tesla being 400 or so means it would take 400 years of its own profits to be able to afford to privatise itself, i.e. returns of 0.25%; being that high is a gamble that future revenue/unit time will go up by a factor of about 20 to bring it into the sensible range.

The upper bound from the grandparent comment for P/E 500-1000, says the annual return is 0.1%, which is what I saw on various current accounts, not savings accounts, not special deals, current accounts.