This is not great advice, the writer is full of himself as a hiring manager. The fact that he could not find the talented that fit the mold he wanted shows it. Kubernetes/Docker/VMs, these are all tools that can be learn... much easier than learning a programming language! Don't shy away from learning them, you can use Docker and then realize the image is full of vulnerabilities.

I want to break down a few things here for those out of school, coming back to from a break, transitioning into software, or stuck in software. You will always NEED to learn, frameworks change (especially in Javascript). Understanding system design and architecture goes a longer way! Knowing more than one programming language is a MUST. C++ has been around for a very long time, getting proficient enough to work programming in C++ is a huge challenge. You NEED to adapt, software is always changing, platforms, browsers (which are much better than Netscape/Explorer from early 2000s), OS distributions.

Domain knowledge is required to build useful software, you are going to have to study the domain, understand it or get an expert... then be able to apply it when building software for it (think insurance, healthcare, missile defense). If you want to build new software with the latest and "greatest" frameworks go for a startup. Game development requires knowing game engines, unless you are building one yourself and most of the time it is in C++. Legacy software requires using old libraries and tools, and maintaining/updating the software is a need... you have to think, who would want to rewrite a tested, stable, and working C++99 application in some new garbage Javascript framework packaged in a browser as a standalone application because the new language and tools are "better"... that would just show your incompetence. What you do here is you learn C++99, if you don't like the job then you switch, but understand your dream job working in aerospace with rockets is going to have C++99, javascript and mongodb in a new startup, or J2EE in an insurance company. Now, if you are looking to hire for any of these roles you would look at someone that can learn and has a solid foundation (for C++ you need to have a solid foundation in C++, for J2EE you could get someone that did Python DJango in the backend, maybe some Java in school, and has done some Javascript front end work).

Best choices in tech would be to join a startup that gets acquired and you retire. For all of us that are not as lucky, your startup can fail and go under, you can get laid off, and the best way to get back up and going is to keep learning. Sometimes going up the corporate ladder is a bigger pain than finding a sweat spot between work and family. Have one scripting language, a programming language for the backend, and know well a native core language like (C, C++, Java, Delphi... knowing those and jumping to Javascript is much much easier than knowing Javascript and trying to learn pointers in C++, it only goes one way in this case). Learn about System Design and architectures, you can take old legacy systems, and add microservices in new languages/frameworks and replace functionality.

A final suggestion would be to not go waiting for things to happen, if you have a job and they don't use Kubernetes or X technology either find a job that is using it and study on your own to get that or go and try to use it in a small project within your organization and stay nimble. Now, if they pay is terrible and your job... look for something else, that usually does not get better, but know that you will have to learn on any new job you get. When you hiring, look for someone curious and wanting to learn with a solid foundation (don't hire a front end Javascript developer to write C++ machine learning code unless he has some certification and project backing that work).