This is different from hiring a remote employee to your company where you've advertised a salary range as part of the job description.
In my experience that's almost always how it works because you have to employ people in such a way that you abide by all local laws. I have seen people employed as independent contractors but, and again this varies by country, there are often restrictions around criteria like how long you can do that for. It's also kind of a PITA for the "employee" because it means they might have to do things like sort out their own taxes and healthcare. If you have a legal entity in place you can do that for them. That means you either set up a subsidiary, or you using a local offshoring firm. And this applies regardless of the country.
Businesses of all kinds offshore labour: small, medium, large, public, private, sole trader, partnerships, VC funded[0], bootstrapped, profitable, loss making, you name it. They all do it for what, for them, are rational reasons. Often very boring reasons. Offshoring can be the difference between profit and loss, the difference between a business that is sustainable and one that is not. A failed business can't employ anyone, whether onshore or offshore.
Now you can argue about whether a business that isn't sustainable without offshoring should exist at all, but that is straying further off topic than I care to go, and frankly is also another rabbit hole likely to lead to unhelpful oversimplification.
You might like to imagine gleeful scheming and maniacal laughter in the boardroom, but I'd confidently bet that that's almost never what's going on in the vast majority of businesses.
[0] You talk about "publicly raising millions": raising funding is not what the vast majority of businesses spend much time doing, and it's not what most businesses who use offshoring spend much time doing.