This is a bit like people being apologetic for PHP. Sure, technically, it is possible to write good PHP code. It doesn't have to turn into a spaghetti.

I have several issues with Kubernetes that superficially look like I'm just avoiding the complexity, but I've dealt with systems that are much more complex with ease.

1. In most orgs and environments, its a cloud-on-a-cloud. A few years ago I used to joke with people that the virtualisation in the cloud is 7 layers deep and no human can understand or troubleshoot it any longer. Adding something like Docker adds 1-2 layers. Kubernetes doubles the layers. Everything you do with the underlying cloud is duplicated in Kubernetes, but incompatible. E.g.:

Azure has: Kubernetes has:

Resource Groups Namespaces
Tags Labels
Disks PVs & Container Images
VMs Nodes
(various) Pods
Load balancers Ingress
NSGs & FWs (various)
Policy Policies
Key Vault etcd
ARM Templates Helm charts
JSON APIs gRPC APIs
Azure AD Pluggable auth
Azure Metrics Prometheus
Log Analytics (various)
PowerShell cli tool

These interact in weird and wonderful ways. Azure NATs all traffic, and then Kubernetes NATs it again by default. There's "security" at every layer, but just to be irritating, all Kubernetes traffic comes from unpredictable IPs in a single Subnet, making firewalling a nightmare. You're running cloud VMs already, but Windows containers run in nested VMs by default on Kubernetes. Kubernetes has its own internal DNS service for crying out loud!

2. Trying to do everything is to be less than optimal for everyone. There are four distinct ways of managing a cluster, and they're not compatible. You can run imperative commands, upload Helm charts, sync the cluster with an entire folder of stuff, or use a plugin like Flux to do GitOps. But if different people in a large team mix these styles, then this causes a giant mess. (To be fair, this is an issue with all of the major public cloud providers also.)

3. Google-isms everywhere. Every aspect of Kubernetes uses their internal shorthand. I'm not an ex-Googler. Nobody at any of my customers is. Nobody around here "speaks this dialect", because we're 12,000 kilometres from Silicon Valley. I'm sure this is not deliberate, but there are definite "cliques" with distinct cultures in the IT world. As FAANG employees flush with cash jump ship to start projects and startups like Kubernetes, they take their culture with them. In my opinion, mixing these together at random into a larger enterprise architecture is generally a mistake.

4. Kubernetes is not much better than bare VMs for developers, especially when compared with something like Azure App Service. The latter will "hold your hand for you" and has dozens of slick diagnostic tools integrated with it. On Kubernetes, if you want to do something as simple as capture crash dumps when there's a memory leak detected, you have to set this up yourself.

5. Microservices and RPC-oriented by default. Sure: you're not forced to implement this pattern, but it's a very steep slippery slope with arrows pointing downhill. In my experience, this is unnecessary complexity 99.99% of the time. Just last week I had to talk a developer out of adding Kubernetes to a trivial web application. Notice that I said "a" developer? Yes, a solo developer was keen on adopting this fad "just because". He was seriously planning on splitting individual REST endpoints out into containerised microservices. He's the third solo developer I've had to talk out of adopting Kubernetes this year.

6. Startup culture. Kubernetes shipped too early in my opinion. Really basic things are still being worked out, and it is already littered with deprecation warnings in the documentation. It's the type of product that should have been fleshed out a bit better at one or two large early adopter customers, and only then released to the general public. But its authors had a lot of competition (Docker Swarm, etc...) so they felt a lot of pressure to ship an MVP and iterate fast. That's fine I suppose, for them, but as an end-user I have to deal with a lot of churn and breakage. A case-in-point is that the configuration file formats are so inadequate that they have spawned a little ecosystem of config-file-generator-generators. I don't even know how deep those layers go these days. (Again, to be fair, Azure now has Bicep -> ARM as a standard transpilation step.)

7. Weak security by default because containers aren't security boundaries as far as Linus Torvalds or Microsoft Security Response Center are concerned. Everyone I've ever talked to about Kubernetes in the wild assumes the opposite, that it's magically more secure than hypervisors.

I get the purpose of Kubernetes in the same way that I get the purpose of something like Haskell, coq, or hand-rolled cryptography. They all have their legitimate uses, and can be useful in surprising ways. Should they be the norm for typical development teams? I'm not convinced.

Maybe one day Kubernetes v3 will be mature, stable, and useful for a wider audience. Especially once the underlying cloud is removed and there are smaller providers offering "pure Kubernetes clouds" where node pools are bare metal and there's no NAT and there isn't an external load balancer in front of the Kubernetes load balancer to make things extra spicy when diagnosing performance issues late at night across multiple incompatible metrics collector systems...