Funnel diagrams are neat and linear because the person drawing one is describing an idea. The actual funnel is a series of jagged handoffs between teams that do not share systems, do not share incentives, and do not share vocabulary. The drops do not happen inside the stages. They happen in the gaps between them.
At a services business I ran growth for, lead capture was genuinely good. Enrollment call quality was genuinely good. Both teams could show you strong numbers for their own stage and both were telling the truth. The losses were concentrated in the ninety minutes between a person raising their hand and a human calling them back, and that interval belonged to nobody.
A warm lead meets a human who does not yet know they are warm. That is the whole failure, and it is invisible in every report either team runs.
What actually fixes it is unglamorous. The context a prospect gave marketing has to arrive with the person who takes the call, in a form they will read in the eight seconds they have before dialing. Not a CRM field nobody opens. The three things that change how the conversation opens. What they came in for, what they already looked at, and what they said in their own words.
Most of what marketing calls conversion optimization is really just tightening that seam. It rarely looks like optimization work. It looks like sitting in on calls, listening to what gets asked in the first minute, and noticing which answers the caller already had available and which they had to guess at.
The reason this stays broken almost everywhere is ownership. Marketing measures up to the handoff. Sales or enrollment measures from the handoff. The gap is in neither scorecard, so it is nobody's bad quarter, and it stays exactly as broken as it was last year. If you want it fixed, put one name on it and let that person change both sides.