Assuming the network doesn't produce external value to the people transacting on it (for example, lower transaction fees than alternatives, lower cost to enforce contracts, lower spread trading equities or currencies etc).
The hypothetical value generated accrues to those who hold equity in the miners or network operators (stakers in a PoS system) - not the tokens themselves. If Starbucks pre-sold coffee as tokens, the fact that Starbucks is selling more or less coffee means nothing for the value of the token.
Let's say I use the network to send $5k to a relative in another country and this transaction costs me $1. If I otherwise would have paid $5, then $4 of value is created external to the network itself.
Currently there are inflationary block rewards so the net may still be ETH creation (depends on the day). That will change after the merge when inflationary rewards are removed though.
They don't, definitely nowhere near the amount currently invested.
"this system is currently costing more than it is producing"
vs
"this system, by definition, is negative sum"
The first is a comment on the current state of the thing, the second is an immutable statement about the thing's nature, which in this case is false.