The phrase "The demands are not equivalent in form, but they are dynamically tethered" means that two or more requirements, forces, or pressures look completely different from one another, but they are constantly and actively connected so that a change in one directly impacts the other.

Here is a breakdown of what this means and the specific definition of "tethered":

What "Tethered" Means

Literally, a tether is a rope, chain, or strap used to tie something to a fixed object (like a dog tied to a post or a boat tied to a dock).

In a metaphorical or conceptual sense—as used in your sentence—tethered means bound, linked, or locked together. If two things are tethered, they cannot move entirely independently of each other. They are structurally joined.

Breaking Down the Full Concept

"Not equivalent in form": The demands do not look the same. They might belong to different categories, use different metrics, or come from different sources. For example, in business, "lowering product cost" and "increasing employee satisfaction" are completely different types of demands.
"Dynamically tethered": "Dynamic" means changing, active, or in motion. Because these demands are tethered dynamically, they exist in a constant tug-of-war. If you pull or change Demand A, it creates an immediate, shifting reaction in Demand B.

A Real-World Example

Think of a smartphone battery and screen brightness.

They are not equivalent in form: One is measured in battery percentage (%), and the other is measured in light intensity (nits).
They are dynamically tethered: As you slide the screen brightness up, the battery drain accelerates in real-time. They are locked in a moving relationship.