How do you adequately explain "opportunity cost” to stakeholders during marketing budget conversations, so that marketing budget priorities are successfully financed?

When discussing opportunity cost:

Define simply.

Show the trade-off.

Quantify the lost benefits (ROI, growth, efficiency).

Use concrete examples relevant to marketing.

Highlight the "cost of inaction."

Emphasize resource scarcity.

By effectively communicating opportunity cost, you elevate the conversation from simply "spending money" to strategically "investing for future gains" and "avoiding missed opportunities," which resonates strongly with financially-minded stakeholders.

I try to use the "Scout Bee" metaphor to help explain opportunity cost. 

In a bee colony, most bees are worker bees: they collect nectar from known sources and return to the hive. Their job is to maximize efficiency and consistency. 

But a small percentage—around 5%—are scout bees. The scout bee's role is not to gather nectar, but to explore unknown territory. They fly off in random directions, sometimes returning with news of a vastly richer nectar source.

So, from a narrow efficiency standpoint, scout bees are “wasteful”. They don’t always return. They burn energy, take risks, and often come back empty-handed. If you were a consultant, bee-optimizing the hive for productivity, you'd likely 'fire' these scout bees.

BUT... without them, the hive would never discover better resources. The colony would slowly stagnate, always going to the same declining flower patch and never discovering the meadow just over the hill.

Let them understand that a resource could be used for A or B or C.

You paint a vision of what one option looks like, and a vision of what the other option looks like. We're in marketing; we should be decent storytellers. 

Thats a great question. 1) Simple explanation 2) Give an example and DOLLARIZE it. Be sure you are prioritizing your investment requests...I'd suggest making it clear what items are longer term, strategic vs. near time and consider Ease of Implementation vs. Difficulty vs. Impact vs ROMI...