This is the structural version of the problem. It describes firms where scaling output requires scaling staff, one for one, every time.
The practical consequence is that the firm can only grow as fast as it can recruit, onboard, and retain full-time employees. In the current US AEC labor market, that pace is slow. Qualified Revit drafters and BIM coordinators are in short supply in most markets. Recruiting timelines run 45 to 60 days for a competent hire, and ramp time to full production output adds another 4 to 8 weeks after that. During a project surge, those timelines are catastrophic. By the time the new hire is productive, the deadline has passed.
The other dimension of this constraint is financial. Every full-time hire is a fixed cost. Benefits, payroll taxes, and overhead make a mid-level drafter's total annual cost to the firm well above their base compensation. In lean periods, that fixed cost is a drag. In growth periods, the firm is reluctant to add it until the need is undeniable, which means it arrives late and under-resourced.
Firms with this structure also tend to be risk-averse about project mix, because every commitment is backed by staff hours, and staff hours are finite and expensive to expand. The firm is essentially capacity-constrained at both ends: too slow to hire when demand rises, too expensive to carry the bench when it doesn't.
What this looks like in practice: a firm lands two significant new commissions in the same quarter. Leadership is simultaneously excited and anxious, because delivering both requires capacity that doesn't exist yet. The answer to that anxiety is not always headcount. A firm with flexible production capacity can staff up the production tier quickly and scale back down after the peak without carrying the fixed cost through the lean period that follows.