The M1 is essentially a large version of the A14 chip and uses the same firestorm and icestorm cores. With such unsubstantial improvements in the A15, the M2 should theoretically also have unsubstantial gains because it will be a large version of A15. The article also mentions that some key technical staff jumped ship so that might somehow halt innovation.

How substantial really depends on the workload. It's small in single-thread performance, but it's easy to grow it with more cores and I'd love to see a lot of background processes moving to more icestorm cores to keep the firestorm ones free.

While IPC is probably not a huge bump, the brute force of doubling the System Cache should yield decent improvements in a lot of workloads on the laptop side.

Could it be that rivals are behind these negative articles and trying to drum up negative PR by spinning them and not telling the whole truth?

Could be. But then it should be easy to verify the facts - did 100's of Apple engineers, along with senior ones, leave Apple CPU division? And does the Apple ARM division suffer because of this talent drain? The whole article makes assumptions based on these facts. Perhaps the assumptions may be exaggerated ... but if people working on the M1 left Apple, it would certainly be an issue for Apple.

Its not just the engineers leaving, the newer chips will also be produced on n4 instead of n3.