Companies reinvest earnings all the time. Some reinvest 100% of the profit they earn. Some reinvest a percentage, and then pay a dividend. If your question is: Why don't these organizations ever stay non-profit, then the answer is: They'd never have the funding to exist in the first place. If they were founded as a non-profit, they don't currently generate enough revenue to pay the cost of building and maintaining these models, so additional investment is needed. Investors want a return on their investment, so for-profit is the only path forward.

> Why can't large scale expensive AI models work when the organisations reinvest the net money they earn?

In order for it to be nonprofit, it can't have shareholders.

There's three good answers I can think of as to why it makes sense to have shareholders (and why "being for-profit" is good):

• Typically, no investor-funded tech company "earns anything" for the first 10+ years of its existence. The way it generally works is that they produce an MVP/idea, demonstrate PMF, and then pitch it to investors. They spend the money they raise, and all their revenue (if any), trying to massively grow the company, and when they run out of that money, they go raise another round, at a higher valuation justified by their growth, essentially until they IPO or get acquired by one of the other, larger, tech companies. These businesses are almost never "self sustaining", because the logic is that you're forgoing growth by not spending every available dollar to grow, and they're principally valued on growth. The way investors in prior rounds "make money" is by selling to investors in later rounds (or simply by making the money "on paper", by marking up their books to the value of the new round). The companies can, in theory, "become self-sustaining" at any time, but in practice, rarely do, until they're absolute behemoths. (Think "The Social Network".) If you believe the thing you do has impact on the world, and you believe that impact is positive, (and if money is very, very cheap,) then it makes sense to spend other peoples' money to maximize the impact.

• You imagine that "whoever owns the company" is essentially some big investors, VCs, wealthy angel investors, etc. and it is. But it's also founders, employees and operators. These people often prefer getting paid some of what they earn in "ownership" (equity) over "salary", because it offers them the opportunity for a liquidity event that will compensate them more than anyone will ever agree to salary them for. This makes sense, because salary is a recurring cost, that the company has to budget for in perpetuity, and buying someone's ownership of a valuable thing is a one-off event. It's hard to make $50mm in salary, it's "easy" (relatively speaking) to make $50mm by owning 0.5% of business valued, by someone, at $10bb. People value that opportunity to potentially make life-changing money, when they know they're doing great work on a world-class product that they believe in. It's like the lottery, but you can control the odds. It motivates people to work very, very hard, and it's a very valuable carrot to be able to offer someone, that is "free" to use for the company from a cashflow perspective, aligns incentives between employer and employee, and is matched in magnitude to the performance of the company and its ability to pay it (since they don't pay it, investors do).

• Profitability is a good yardstick to ensure something is sustainable long-term because it's impartial, it's directly related to sustainability (producing more than you consume means you're generating excess value for someone else), and it forces people to make hard decisions, since it aligns incentives toward sustainability and away from sentimentality. The economy operates in credit cycles. It's a company's job to be able to navigate these cycles, and survive the deleveraging part of the cycle. Part of its ability to do this can stem from its ability to access capital markets to generate liquidity when it needs to. It's harder and much more expensive to borrow money if you don't have equity value. It's also very easy to spend the excess generated during the leveraging part of the credit cycle, and mistake it for durable "growth" (just look at the budgets of any government).