I think the idea is that the use of a particular tech stack isn't a determinant factor in terms of product quality.

Tech stack and product quality are highly correlated in the real world.

Sometimes it is, but generally speaking, I don't think so. The correlation appears to be pretty loose in the real world.

Well, the alternative and more charitable interpretation would be that you are more likely to build a better product in the stack you know well and enjoy.

I think when you get more concrete about what the statement is talking about, it becomes very hard to assert that they mean something else.

Like if you are skilled with, say, Ruby on Rails, you probably should just use that for your v1.0. The hypothetical better stack is often just a myth we tell ourselves as software engineers because we like to think that tech is everything when it's the product + launching that's everything.

!= "Use the tech stack that cheapest developers can work with".

(Yes, for real. I've once witnessed this being said out loud and used to justify specific tech stack choice.)