As Marc Andreesen once put it: "The only thing that matters is product/market fit". Fuelling the growth engine and entering the high growth phase does not make sense if a company has not yet found product/market fit.
But as product/market fit is not binary the question arises how to measure product/market fit?
Founders may gather and analyse quantitative and qualitative information and need to use their intuition in order to assess whether they can start scaling heavily.
In 2017, I wrote this article about the importance of pursuing the ultimate goal of establishing a profitable business. Given the recent IPO developments (e.g. WeWork and others), this article seems to be even more relevant today.