This thread isn't really clarifying or defining what a "great" culture constitutes, and it strongly suffers from survivorship bias.
The author is pointing out that a necessary ingredient (among others omitted) is strong culture--which is something of a tautology. Of course a company with great culture has a strong culture; if it were a weak culture, it wouldn't be pervasive or definitive of the company. A company with weakly held cultures wouldn't be described as a "company with great culture". At best it would be described as a "company with great team cultures", at worst a "company without culture". But none of these three statements hold any inherent truth about how productive the company might be, how happy people might be working at said companies, the values of the people working for these companies, or how the collective values of the employees impact the company.
The author is also looking at two companies that have been around for 15+ years. Where is the evaluation of all the companies with similar leadership values to Amazon and Facebook that didn't survive? Was their strong culture an aid or a hindrance? Did they fail despite their strong culture or because of it? Where is the evaluation of companies with similar success and longevity that don't have top-down cultural values? Can we say definitively that they don't have great culture?
I appreciate that the author has a lot of respect for and values the culture of previous employers, but when asking the question "What defines a great company culture?", I would hope for a more substantive answer. Reinforcing that "whatever the cultural values might be they have to be strongly endorsed by the leadership" can be part of that, but that's describing something other than the "great culture" itself.