* Does it require a big capital investment? the company provides that.
* Is it risky? The company gets a risk premium.
* Does it need a bunch of specialized resources? the company needs to provide those.
* More subtly, is it net-new or incremental value? Providing a company with something that boosts what they already do isn't evaluated on the incremental increase because you can't realize them without the previous baseline.
There are countless factors measuring value-add, making it extremely hard to allocate back to a single cog in the machine - unless you're a startup with very few cogs, hence they're responsible for all value (or costs).
If you want to be evaluated based solely on your individual contribution, put yourself into a situation where this is possible, i.e. do it all yourself. Otherwise join the broader team and take the benefits and costs that comes with that.
What if the advancement is in the wrong direction in the market? Like Windows Mobile was. You could have built a great system that delivered a few hundred million in sales, but two years down the road it cost the company a few billion in costs. Do you get to pay back your share?
I'm not advocating here for the work to be uncompensated - it's just when you get a risk shield, you also lose the payout shield.
Maybe a better culture of coop's would be a better solution.
If someone who can consistently deliver great value to a company is let go, they can go elsewhere and provide their value as a consultant or employee. You seem to think the company has no competition and doesn't need to compete with other businesses in the marketplace. I think you are also overlooking the fact that most interns are hired to see if they will be good to bring on full time. Some of them turn out to not provide substantial value. If an internship is how you are demonstrating your value to an employer, then your contribution is being average across all the interns that don't contribute anything or much of anything.
Also, the company probably only has to pay those $40k to $200k in salary costs for a few years, but the benefits derived from the work might outlive it. There's nothing stopping anyone from firing an employee just because they previously made a massive contribution to the company's financial success. Why keep the cow if you can get the milk for free?
So it might even be the full $500k in pure profits after the 2nd year.