Perhaps not. The EU would be the best example of a “soft conquest”. The EU offers a bunch of carrots to member states - but requires that they adopt democracy, a stable government, various principles on human rights, allow free movement of other EU citizens, adopt the euro, and so on. Also total failure countries like Greece are being handled somewhat differently.
I could see a situation arising where a single world power manages to develop some really compelling technology. Something that requires a highly sophisticated economy to develop, a mass effort that uses software systems more sophisticated than anything we’ve ever seen. The product would of course be a medical system capable of curing almost all disease and reverting a person’s biological age to their physical peak.
Anyways I could see the powers that have something like this using it as leverage. If you think about it, any nation that refuses terms is having it’s own citizens die from disease by the millions every year. I don’t know about you, but if China had this tech and I had to renounce my citizenship and flee this country to get it, I would. Wouldn’t you? Wouldn’t all your neighbors?