Nothing wrong with ASGs, but they're not really comparable to k8s. k8s isn't simply "scaling", it's a higher level of abstraction that has granular control and understanding of your application instances in a manner that allows it to efficiently spread workloads across all your hardware automatically, all while managing service discovery, routing, lb, rollbacks and countless more. Comparing it to ASG suggests you may not be that familiar with k8s.

I think it's fair to argue that k8s is overkill for many or even most organizations, but ASG is not even close to an alternative.