The nodes running out of fiat is a balance-sheet problem, not a demand problem: you take payment in sats and owe the upstream provider dollars, so every operator is short fiat against a long bitcoin float and one bad week on the chart eats the margin. Many providers also prohibit reselling API-key access, which puts the operator on the hook for terms they did not negotiate, and the personal card behind the key is a single KYC chokepoint for the whole node. Pre-funded provider credit with a sats price that tracks it would let a node survive a drawdown without going dark.