It is a common assumption (and, as far as historical stock market data goes, also proven) that the stock market is always growing if you enlarge the time window long enough . In other words: *The stock market always goes up in the long term*.

Is, therefore, the conclusion valid that you can totally invest as much as you want at any point in time you want and you can never go wrong, if

1. You diversify strong enough (invest "in the world")
2. You do not need to urgently sell your assets at any point in time

If yes, all that strategies that rely also on diversified, long-term investments (Dollar-Cost-Averaging & Rebalancing, .. what others do you know?) are just to *optimize* the yiels, but you'd make profit even without those strategies. Is that correct?