That wouldn't really work; the ME is essentially "the CPU" of the Platform Controller Hub. Disabling it would be disabling your computer (e.g. your IOMMU, your DRAM refresh, your ACPI command routing, etc.)

All the stuff that used to be done "manually" by the CPU itself back in the 8086 days—using configured IRQs and PITs and whatever else—is done autonomously by the PCH these days, with the CPU just asking the PCH to "get it done." And the logic that runs in the PCH to interpret those requests and decides when and how to apply them, is executed by the ME.

The ME only managed to not exist previously, because mainboards were previously both "simpler" (every bus spoke exactly one protocol and the controller chip for that bus did the protocol signalling) and more complex (tons of single-purpose controller chips.) The PCH boils all that down to one chip, and it needs a CPU to do it, and that CPU is the ME. Getting rid of it would mean going back ~15 years in computer capabilities.

(Another way to think of the PCH is that it's basically an SoC chip, with the "heavy lifting" of application execution moved out to a separate, upgradable CPU socket. But, like any SoC, it still does need some sort of internal CPU. The ME is that CPU.)