Your attempt to make economics "basic" is the problem. Wealth is both created and destroyed. It is a fiction. You can't write it as basic arithmetic and find conclusions that even make sense. Like, I'll give you the laziest counterpoint in the world: you say that if someone makes a company and hires people and the value of the company goes up, the owner took that value from the workers. What if the value of the company goes down? What if the owner loses money? Did the workers steal that value? Did somebody steal that value? Or is your "basic numeracy" basically nonsense?
Why did the value of the company go down or why did the owner lose money in your hypothetical?
Those are questions you must ask to get at what is actually going on. For example, a worker could generate lots of produce but the company might not put enough effort into (which is to say hiring other people to perform the related and necessary task of) actually selling it and so it sits in an inventory somewhere and spoils or the loans that were to be paid after its sale default. The value produced by the worker isn't realized to the capitalist in that case, but that doesn't have anything to do with whether the worker created value in excess of their pay; the value was squandered by the business.
Or the company could be perfectly profitable, but then the owner decides to sell off a bunch of assets and pay the CEO (perhaps himself) a bunch of money while laying off a bunch of workers and cutting production by 90%. The value of the company's stock will have gone down (presumably-- this isn't
necessarily the case, but assuming a bare minimum of market rationality it will be), but you can scarcely say that the workers are any less exploited than in a profitable enterprise that hasn't been gutted in the same way.
The workers are responsible for producing the product that is sold by the company whether the company is profitable or not. The owners are not responsible for producing the product that is sold by the company whether the company is profitable or not. If the workers in aggregate are overpaid with respect to what they produce and sell, we don't regard that as workers stealing from the owner because owners are the ones in a position to set terms. Owners are the ones who can simply not continue or not start in the first place, restructure the business and so on. Granted, some businesses are so small that an owner straddles the line between employer and employee such that they can feel trapped into continuing once they've started, and this can be compounded if the assets of their business become too entangled with the assets they use to live (as, say, someone who works as a hair stylist out of their own house). This is why most people who don't have money to begin with are well advised not to start a business.
The reason profitable ventures are the archetypal case that we should analyze is that unprofitable capitalist ventures do not reproduce themselves. Profitable ones do. So, despite shockingly high rates of business failure in capitalist societies, what dominates the structure of our economy are the successful businesses that profit. This doesn't necessarily mean that they have an
accounting profit, as they might avoid positive cash flow by reinvesting all profit into expanding production. But it does mean they have disposable income, that the cost of the resources necessary to make the product (including labor) are less than the amount they receive for selling the product. If a business cannot achieve that in the foreseeable future, then it is well advised to restructure so that it can, or if that is impossible, to simply stop all operation (and not "throw good money after bad").
This sort of analysis can be even more micro, of course: any individual employee ought to enable a business to make more money than it could without that employee, else that employee should be fired (if maximizing profit is the only concern, anyway; it isn't always).
The analysis can also be more gross. Take, for example, the slave plantation operating in a market economy: what if the plantation has to spend more on maintaining its slaves than the slaves produce for it? Do we then say that the slaves are stealing from the master? No, we say that some people are about to be sold or brutalized (or both). Because power relations are relevant. The master is the one setting terms and the one in a position to restructure (which is to say sell slaves, feed them less, whip them harder, choose a different crop, and so on) or decide to simply fold the enterprise and sell off the land. This dynamic didn't disappear in the transition to capitalism, it was simply transferred to a contract by which workers, instead of being sold or whipped harder would be fired or paid less in cases where their produce is regarded as not enough to justify their compensation.
So anyway, what was the objection? You asked some questions and vaguely asserted that they raised some kind of problem, but it's really not apparent how. Just because the analysis of successful firms requires only basic numeracy doesn't mean that there are not answers for questions about unsuccessful firms.
I'll boil it down: Jeff Bezos can sell Amazon for whatever multiple of a hundred billion dollars, and the workers are responsible for creating the company that people think is worth that much. Jeff Bezos can decide to sell or not; the workers cannot. Why is the company worth so much? Precisely because people think that the value produced by its workers for its owners far exceeds the amount paid to its workers. It could scarcely be otherwise unless Jeff Bezos had literally invested 100s of billions into the company in the first place, or he bought the actual Amazon River and discovered a huge deposit of copper or something worth that much afterward, neither of which is the case. If you want to say that a lot of the value of Amazon is based on monopolization, I'd be inclined to agree, but that monopolization would be impossible without, you guessed it, the workers.