“If you track the cash, to the first worker ,then are all costs eventually be labour costs?”
No.
People have already mentioned materials, and no, material costs are not labor costs “down the line” – the costs of materials are usually determined by the market for them, which may have some component of labor, but is also just the market cost of the thing. When a mine owner sells stuff he mines, he’s going to charge what the buyers he knows are willing to pay. Sure he probably pays something to maintain his operation, part of which expenses involve miners (and/or slaves) but they also involve other costs, and are less that what he sells the materials for – if he mine owner starts to see the costs start to approach what he sells them for, he’ll consider getting out of the business (or reorganizing it).
Tax was also mentioned and also isn’t labor-based.
There are other government fees, banks claiming interest and fees, tariffs, other money paid that isn’t about labor, various types of contracts, bribes, food, rent, gambling, anything anyone pays money for.
And on top of that, all payments are made based on an agreement to pay of some sort, and are fundamentally arbitrary. Think about gaming micro-transactions for imaginary hats or pets or the ability to play Darth Vader or whatever – utterly made up prices, and totaling billions of dollars in imaginary game nonsense. Next look at bank fees. Some banks charge $5 to use their ATM, or monthly fees to have accounts, or other fees that other banks don’t charge at all – guess what? They’re all made up and the basis of them is banks acting like pompous authoritative ass-hats and cartels to get people to pay them. Or the amount of labor fees themselves – all made up. Now, the people making them up and agreeing to them are part of a huge swirl of other made up prices and situations and conversations about it so that there is an appearance of them making some sort of sense in relation to each other, and there are computers tracking how much we all supposedly “have” so it seems real and we can pretend if makes sense so we don’t notice how ridiculous we all are, but it’s much more imaginary agreement-reality than it is concrete anything.