I'm in a $1b one now and there's plenty of challenge, lol. It could be the SE Asian ones are a little different. Because you can't just focus on one country, there's a lot of smaller ones with very different cultures and legal frameworks. So a big company ends up spawning off a new company every 6 months or so and have to figure it out again. It's why companies like Stripe, Uber, Amazon have so much trouble with local competitors wherever they go. And it's why companies need to expand quickly, before a local competitor grows enough to challenge a regional one. We've had situations where a payroll or messaging app might have 90% adoption in one country, but near 5% or so in a neighboring country that speaks the same language and eats the same food.

LATAM and Africa seem to be similar too. Former colonies, so there's a mix of similar ethnic background and yet different work/life/economic/legal cultures. And places where corruption is heavy, where private organizations may pick up the slack from government.

Again Rocket Internet is pretty good at this kind of thing. If the Americans are like colonial Great Britain and the Chinese are like colonial Spain, Rocket Internet is like the Dutch East India Company.