Every annual planning cycle I have sat through worked the same way. The product org submitted a headcount plan, more output meant more people, and the cost grew in predictable steps. The CFO could draw the line a year out and trust it. The entire ritual rested on one assumption: that output scales with heads. That assumption is quietly breaking, and the planning processes built on top of it have not caught up.
How product used to be budgeted
The model was clean. Headcount was the unit of capacity. You sized the team to the roadmap, the cost was salaries plus overhead, and it grew in steps as you hired. It was fixed in the accounting sense: a quiet week and a launch week cost the same. That predictability was a feature. It let finance plan, it let the board model burn, and it let the CPO defend a number.
What changed
Output stopped being a pure function of headcount. A team of six running a fleet of agents now produces what a team of twenty used to. I have watched this directly, and the math is not subtle. A meaningful share of the capacity now comes from compute, and compute shows up as tokens, tool calls, and GPU time, not salaries. It has the opposite cost shape from headcount: variable, not fixed, scaling with usage, not the org chart. Blend a fixed headcount line and a variable compute line and the combined product cost stops looking like a payroll line and starts looking like an infrastructure bill.
The three things that change
You budget output, not heads. The planning question shifts from "how many people do we need" to "how much outcome do we need, and what does it cost to produce." Cost per outcome replaces cost per FTE, which is uncomfortable because it is harder to forecast and easier to be held accountable for. That discomfort is the job now.
Marginal cost stops being zero. Under the old model, once you had hired the team, an extra unit of work was free. Now every agent run has a price, so a poorly scoped agent burning tokens on low-value work is a line item, not just a process smell. Quality and efficiency move from engineering concerns to budget concerns.
Capacity becomes elastic. You could never scale a human team up for a launch and down the week after. You can do exactly that with compute. The orgs that exploit this run leaner baselines and surge when it counts.
To plan this way, instrument compute spend at the workflow level, then bring finance one blended picture: the fixed headcount line, the variable compute line, and cost per outcome as the metric that ties them together. Pull one number this week: your total agent and compute spend for the last quarter, divided by a unit of output you care about. Most CPOs have never calculated it.