Better still: change the definition of "growth" to encompass more nuanced, non-quantifiable things like user happiness, employee happiness, etc.

I agree in general, but network effect companies are highly vulnerable to being out-grown. A bigger rival with a bigger network is inherently more attractive to users, and it's competitive advantage increases exponentially with size.

The only way to avoid that I know is to address a specific target audience and scale up to dominate that. Tumblr has achieved this. A rival then can't dislodge you because you already own the relevant network. It's still risky though, because if a rival builds a product that covers the general audience and also servers that subset well, then the subset might decamp. Hence Tumblr trying to break out of it's niche. G+ addressed a lot of niches very well, but Google just wasn't interested in that kind of network.

on of my favourite books is "Small Giants: Companies That Choose to Be Great Instead of Big" by Bo Burlingham. It's worth a read if this is something that interests you.