I don't think it matters if it was a k8s issue or not, what matters is that k8s made it much harder to get to the bottom of it.
We actually had similar issues when we deployed k8s. In the end it turned out to be a misconfiguration, but took weeks to figure out, and only because our entire dev team looked at it (and not the k8s guru who implemented it all).
The problem is that a k8s cluster requires hundreds/thousands of lines of yaml configuration just for the core components, including a choice of network overlay. Everybody copies the same default configs hoping they will work out of the box, without understanding how each option actually affects the cluster. Add to this the container and yaml upgrades that should be applied per component every month or so, and it's nigh impossible for most companies to handle.
Kubernetes is far too complex to set up from scratch. The only way to reduce the complexity – or rather, to offload it – is to use managed Kubernetes via AWS or GCE. The fact that using AWS or GCE is effectively the only viable method for running a production Kubernetes cluster speaks volumes to how non-simple the stack truly is.
New kubeadm makes is easier to set up a cluster from scratch. But the complexity truly is there and it's difficult to understand all parts of it. But - clusters are complicated. Running hundreds of workload jobs in a manageable way shouldn't be easy, right? Maybe it is not a problem of k8s but the fact is we now require complicated stack with many moving parts and it is not easy to manage it reliably.
You need to be able to debug and separate out problems no matter your infrastructure.
You'll get lots of SMEs that can use a product but can't trace or profile, and it isn't the underlying products fault beyond hype driven development.
If you want to spin up ephemeral environments to test your code, kube is one of the easier ways to achieve this. Similarly, it helps you solve problems such as app health, dying nodes, etc.
It's a great product, especially when you've scaled past a single app and a single team, but that's largely because it's a framework, similarly to how rails is, and if you do something serious with it, you need to know how it works.
The alternative is you build your own framework, but your new hires will prefer k8s.
Realistically though, use GKE and forget about it until you grow. Otherwise you're using something closed or something bespoke, the latter being fine for a 1-2 man team, but kinda pointless when you can have a managed service.
If you read the book you would not call it advertising material. It's very open-minded and it's honestly not a book that is designed to sell you on Pivotal PAS in any direct way.
The first line in the first chapter is more like an "ok, full disclosure, this is advertising material" but if you read the full text, the Pivotal suite of tools is hardly mentioned. It merely paints a picture you can understand to demonstrate that some kind of platform is definitely needed for basically any enterprise of nontrivial size. (Now if you want to read the real promotional material, get yourself a copy of "Cloud Foundry the Definitive Guide")
This book is only advertising in the sense that if its message is delivered successfully, you will concede that you should use a platform, and we will both agree on the meaning of the word platform. That's it. It's only a bit of tongue-in-cheek first since Pivotal actually makes such a platform, that it says on Page 1, "our platform is the best and only platform" – the rest of the book isn't at all like that.
But if you take it in context for the date of publication, it might make more sense that it was framed this way. Obviously it does not pre-date Heroku. It is a different platform than Heroku. But it is a platform, and a cloud-native one. It's an example of "why you might not need Kubernetes." Also might help to note that this book was published in 2016.
It might be (read: definitely) harder to assert in 2019 that there really isn't any other platform worth considering (than CloudFoundry in 2016), but for a medium-large enterprise in 2016 I'm honestly not so sure. Kubernetes was still new on the scene. People in 2016 in large part still needed to be convinced that such a platform was needed, or even possible, since few existed in the wild/open source commons. (Name your favorite platform that is older than 2016, if you still are in disagreement with the thesis. There are sure several right answers, and I seriously don't doubt this at all.)
To take the contrary position to the extreme a bit, present company including the original poster I think nobody serious (I hope) is suggesting "you may not need Kubernetes, and there is also no serious contender which you should consider in the race for a thing like K8S that you may need for your enterprise, either." Even the original post recommends something instead (Nomad). There is a decent chance you are already sold on this idea, if you're reading this article.
The central argument isn't that you should definitely pick Nomad, it's that you really do need a platform that works for you, even if it only gets you 80% of the way there. The author of "Maybe You Don't Need Kubernetes" started out explaining why Kubernetes just wouldn't work for them. The book, just like this article, comes off a bit like "hey, why not this product instead of whatever it is you're doing there."
But just a little. I strongly agree myself – "In 2019, pick something, anything. (Even Nomad) Just don't do nothing."