Love this (also love that book and have read it multiple times since b-school). 100% agree that it's all about looking at the Limiting Factors in the business (funnel / pipeline, etc.) and then solving for those.
I do think there is a set of agent usage which is useful to learn the boundaries (in engineering, in sales, etc.) but to your point running 20 agents is like turning the over up to 600 to try and get a cake to bake quicker.
Eli Goldratt's book, The Goal, was famous for its (then unpopular argument) that keeping every machine running 24 hours a day, the metric most plant managers cared about, was actively making factories worse. I suspect we're seeing the same fallacy in how many people are using AI agents.
Goldratt's point was that machine utilization isn't throughput. What you want from a manufacturing plants is making good widgets as cost-effectively as possible.
It doesn't necessarily follow that running your machines all the times optimizes that.
Picture a three-station assembly line. Stations 1 and 2 each crank out 200 widgets an hour. Station 3 can only handle 100. Running stations 1 and 2 around the clock doesn't ship more product. It just piles up half-finished widgets in front of station 3, ties up cash in inventory, and creates more work managing the pile.
He developed the Theory of Constraints to point out that what matters is solving the bottleneck in the system, not increasing machine utilization.
I suspect a lot of agent usage right now is the same fallacy at higher resolution. Running 20 Claude Code sessions in parallel can feel productive because something is always happening. But, if the bottleneck in your work is judgment about what's worth doing, more agents just generate more output for you to wade through.
This is not to say there aren't workflows running 20 agents in parallel very effectively, I'm sure there are. And, I suspect there's a general retraining we all need to do around evolving historical workflows. But....
The constraint for most knowledge work is deciding what's worth executing and no one is task switching between 20 things at the same time effectively I don't think. I find I can run maybe 2 or 3 things in parallel with maybe 1 or 2 admin-y type things on the side and that is only if I'm very locked in.