But the decision to make server chips entirely of E cores must come from some customers demanding core count density above all else. I'm suggesting where that demand comes from.

> (...) must come from some customers demanding core count density above all else.

I don't think you realize that that's not a niche, whimsical requirement that you can only explain with conspiracy theories.

For decades, all hosting providers have been paying a premium to have more computational power with a smaller size and power footprint.

This is not a AWS whim. All cloud providers want this, and have been paying a premium for this. If anything, AWS had the budget to roll out their own CPUs.

How long ago did AMD launched its Bulldozer line?

Modern CPUs are mostly limited by their energy budget/heat and smaller cores are more efficient. Also, if you have a workload scaling to, say, 8 cores chances are good that it also scales to 20+, allowing the usage of many small cores. Hence, having a few fast and then several smaller, more efficient cores should be also useful for workstations and servers.