I enjoyed the article and mostly agree with the authors opinions, but I think it glances over some important shifts in modern economies.
1) It is becoming increasingly hard to stay small if you have a competitor taking advantage of economies of scale and network effects. 2) It is becoming increasingly common for new sectors to discover economies of scale and network effects as digital transforms products and services.
So from a game theoretical point of view, it is kind of inevitable that "being the best" will start to be shadowed by "being big" if size becomes relevant for survival.
If you don't want to be part of something big, the alternative is to build something incredibly differentiated (like sake with 800 years of history).
Basecamp is cited in the article and their approach is exactly this. They build something incredibly differentiated like Hey (a 100 USD/year email service). But "email services" is not a market with significant economies of scale nor network effects, Google and Microsoft would not offer such service for free if it was.
But if you're interested in, say building a job board, where there are strong network effects. You'll never be able to be at peace regarding size. As soon as a direct competitor becomes bigger, you're in danger. There is room for a few medium size contenders, not infinitely many artisans with their slow-going shops.
The thing is: if you open a sake brewery today, can you survive long enough to make it highly differentiated and earn your place in the market? Not an easy task. So I don't blame founders if most companies today are born with growth in mind. Some if it might be tunnel vision and articles like these are good to remind everyone that "big" is not the only option, but it's not like the other options are always feasible either.