The main focus of the post is to highlight some of the long-term risks and consequences of standardizing around Kubernetes in an org. If you've done a proper evaluation, and still think Kubernetes makes sense for you, then it's probably a sound decision. But I think many skip the evaluation step or do it hastily. The post is more targeted towards organizations with at least a handful of employees. What works for an indy dev does not necessarily scale and work for SMBs or larger orgs - those are very different contexts.
> The article suggests just using EC2 instead of K8s
Not quite. I suggest strongly considering using managed services when it makes sense for your organization. The equivalent of k8s in terms of managed services would be Amazon Elastic Container Service (ECS) as the control plane, perhaps with AWS Fargate as the compute runtime.
(I wouldn't really call EC2 a managed service - it's more in the territory of Infrastructure as a Service)