To me, this discontinuation is less about the product and more about making a statement. The M2 Mac Pro was a dysfunctional product of an internal conflict of interests, but it cast a ray of hope that the M series would develop past the current scaled-up-but-still-disposable phone/embedded SoCs and that Apple had some interest in bringing them closer to the offerings of the competitors from the workstation/server market. Now, with this move, they've made it clear that they would rather give up an entire segment than make at least a narrow part of their ecosystem open enough for the PCIe slots of the Mac Pro to find any serious use.
To me, this discontinuation is less about the product and more about making a statement. The M2 Mac Pro was a dysfunctional product of an internal conflict of interests, but it cast a ray of hope that the M series would develop past the current scaled-up-but-still-disposable phone/embedded SoCs and that Apple had some interest in bringing them closer to the offerings of the competitors from the workstation/server market. Now, with this move, they've made it clear that they would rather give up an entire segment than make at least a narrow part of their ecosystem open enough for the PCIe slots of the Mac Pro to find any serious use.