The only way to genuinely control captured territory on the ground is with infantry, and it'll remain that way for a while yet. America demonstrated the limits of what you can do with Predator drones in Afghanistan; the tech worked great and posed a huge threat but the Taliban was never truly defeated and continued training and recruiting at scale.
For something like an invasion of Taiwan or (gulp) other territories beyond that, the only way to completely subdue the captured population is with lots of soldiers.
That was true 10-20 years ago, but in a world with "terminators" I don't think it's true anymore.
Regarding effective conquest, we can look at the historical lesson of Rome. Conquest is effective when you can co-opt local leaders and cultures to cause them to identify with the conquering culture. Conquest that doesn't cause integration is historically unstable.
For something like an invasion of Taiwan or (gulp) other territories beyond that, the only way to completely subdue the captured population is with lots of soldiers.