Computer science doesn’t have the EE pre-requisites to do DSP while computer engineering does. We aren’t actually engineers, we didn’t get to take classes in the engineering college, maybe we should have.
Incidentally a lot of AI movers are EEs, not even CSE or CEE.
ECE is a compromise track that limits how far one can progress on hard systems design problems. An ECE’s principal strength is that they tend to manage long term software projects better than EEs.
EEs lead in anything that is limited by physics because that is how the discipline is oriented. The bleeding edge of compute has been like this since the first microprocessors were created, at the very latest.
Incidentally a lot of AI movers are EEs, not even CSE or CEE.