The cloud bill is the only number in most companies that nobody on the team owns until it's already a problem.
Engineering owns latency. It owns error rates, p99, uptime, the whole observability wall. Finance owns the invoice. And between those two ownerships there's a gap wide enough to drive a fifth to a third of your cloud spend straight into a wall — which, across the industry, is roughly what happens. The fix isn't a smarter spreadsheet at month-end. Real cloud cost management isn't an accounting function at all — the fix is to stop treating the bill as accounting and start treating it as a product metric: cost per request, cost per tenant, cost per feature, sitting on the same dashboard as latency and error rate, owned by the same people who own those numbers.
That's the whole argument. The rest of this post is why it's true and how it's done.
The bill is a lagging accounting artifact, and that's the bug
Here's how cloud cost is treated almost everywhere. A bill arrives. Someone in finance reconciles it against a budget. If it's higher than expected, a thread gets opened, an engineer gets pulled in, and everyone spends a week spelunking through Cost Explorer trying to reconstruct why a number that's already been spent is what it is. Then it happens again next month.
