From our Western sensibility, that both Holo and Niji have built and maintained a presence in Indonesia compared to what one would think would be a more profitable market like Korea or China feels really… random? I can only imagine that there's some sort of massive, money-spending weeb front there under the surface which has made it worth their while and their paths just don't intersect with western weebs that much. I hope we can get more backstory on that some way or another some day.
To understand Japanese industry's obsession with places like Indonesia requires some autism, so I will provide it.
In the modern globalized economy, there are broadly two types of national economies: export-led economies (production > domestic consumption) and import-led economies (consumption > domestic production). The factors that determine which type of economy you are are quite varied, but usually the primary determinants are age structure and national wealth. Let me explain these:
1) Age structure. An economy with more young people than old people tends to be consumption-driven. Young people need houses and food and childcare and entertainment and a whole litany of other things that they often cannot afford. They consume more than they produce in an industrial economy. Older people (middle-aged till retirement) have outsized human capital (productive capacity > consumption capacity) but little incentive to consume (since they're past childbearing age and often have most of the things they need already). An economy like Japan is outrageously old. It's probably one of the oldest countries in the world by median age. Domestic consumption has declined since the late 1980s. Indonesia is very young and still has a growing population (read: consumers for products potentially made by Japanese companies).
2) National wealth. Being young isn't enough though. A nation-state must also have some kind of wealth (or at least, the potential of it) to be viable. Indonesia has a bustling primary product sector (oil, agricultural products, etc) and lots of available labor. A country like Japan looks at a place like Indonesia and thinks, "They're not rich now, but if we start accruing Indonesian assets now, we can use those to acquire Indonesian resources in the future."
That Cover expanded to the English market around the same time it expanded to the Indonesian market and consequently let the Korean market wither on the vine makes perfect sense in this paradigm. The Anglophone world is relatively young (in a spectrum of median age, you have something like Southeast Asia>US/France/Australia/Scandinavia>UK>Eastern Europe>Germany/Korea>Japan). EN's markets are a little older on average, but still young enough to be primary consumers (see continued Japanese interest in the US auto market) and they also have a great deal of wealth. Indonesia is poorer but also younger, and so the potential of getting in now is still there (especially with how cheap Indonesian talent is comparatively). Korea, on the other hand, is an aged economy. It competes in the same consumer markets as Japan and already has a basically-saturated entertainment market with few consumers left to exploit. China is still young enough right now, but its closed capital account (read: no guaranteed access to Chinese assets to buy shit down the line) and its rapidly aging demography means there was probably never a real future for Hololive CN and so cutting it was an easy choice.
Caveat 1: Not all countries age at the same rate. The aformentioned anglophone world is aging relatively slowly compared to most of its peers. The US has a birth rate that isn't replacement, but still high enough to gradually taper the economy into middle-age rather than the rapid changes that places like Japan experienced (the US also has a culture of gradual onset adulthood that means that many Americans remain solid consumers well into their 40s). China, for example, went from being younger than the US to being older than the US in just 30 years despite starting almost a century later than everyone else. For companies that sell consumer products, the US is the equivalent of a blue chip stock while Indonesia is a risky start-up company.
Caveat 2: Some national economies never properly globalize and so don't adhere to these principles. India is young and has decent national wealth, but political policies have severed its ties with the global economy (internal consumption = internal production, if there's underproduction, there's underconsumption).
