Regarding skills not being transferable. This is only somewhat true and the author is doing some goal post shifting here. What he said really only applies to game engines, not game frameworks and certainly not game programming in general. If you want to learn game programming and not a game engine, I recommend using something like Pygame or LOVE2D which are less prescriptive game frameworks as opposed to engines.
However, even with game engines, I have spoken with AAA developers who have worked with both Unity and Unreal and they all say the same thing. Game engines are a lot like programming languages in the sense that once you learn truly learn how one works, picking up a new one isn't that difficult.
> Game engines are a lot like programming languages in the sense that once you learn truly learn how one works, picking up a new one isn't that difficult.
As someone who has worked as a AAA game dev for almost 13 years, can confirm this analogy holds true. Off the top of my head, I can recall 8 different game engines I've worked on (all proprietary). You start to pick up on the common patterns and ideas between them, and learning a new one boils down to figuring out familiar interfaces. Just like when learning a programming language, you look for the fundamentals (loops, conditions, data types, etc).
At the end of the day, "game engine" is a fancy way of describing an amalgamation of systems that gather input, maintain a complex state machine/simulation, and draw it on a screen. And from my experience, the way different engines accomplish this doesn't truly vary that much.
The studio I'm at has hopped around a bunch, so I've gotten to do work for a range of franchises over the years. Guitar Hero/Band Hero, Call of Duty, Skylanders, Crash Bandicoot, Destiny 2, and most recently Diablo II Resurrected. And also quite a few different platforms (Nintendo DS/Wii/Switch, PS3/4/5/Vita, XB360/1/SX, Apple TV and iOS).
I've mainly done engine and tools work, often for UI or scripting systems. From my experience, each studio and franchise tends to make its own custom engine and tools. Although, in some cases we managed to reuse a decent amount of in-house technology across projects. The Tony Hawk remaster was an unusual case which used Unreal Engine instead.
It's given me an interesting perspective behind the scenes of AAA games. These titles may all use different software but they're fundamentally built on the same principles. Once you get the gist of how games like this are put together, learning another isn't a big stretch.
I would argue the opposite, there's a really strong skill transfer between gamedev(esp on the engine side of things) <-> embedded development. Both deal with hard constraints(performance, memory, storage) and you use similar approaches to deal with them.
At a more high-level HMI/game design has a pretty large overlap. No one knows what "fun" or "easy to use" are, so the approaches to converge there are similar(rapid prototyping, etc).
Yeah I spent a little over four years in the game industry and successfully transferred to enterprise and web development (while still doing some games on the side). I'd say there's quite a bit of overlap depending on the tools or languages you use.
And yeah, I've switched between many game engines over the years myself. Unity, Love2D, Flash Actionscript, Pico-8, XNA, Cocos2D, QBasic, TI-BASIC (texas instruments calculators), Hypercard, PyGame, Popcap Game Framework (C++), straight up OpenGL, J2ME, Kindle Active Content (basically Java), PhaserJS, and Swift + SpriteKit. It's about as transferable as going from Angular to React (which I did when I switched jobs six months ago). Yeah you have to learn how to do some things differently but you can pick up the new one pretty quickly if you've had experience with the other.
I do have a lot of unfinished projects, but that's also true for me for websites, apps, writing, puzzles, and board game designs as well. It's not specific to video games. Also most of them are unfinished because I got distracted by other projects or decided to go a different direction, not because game dev is hard (although it can be). I do have about 20 video games I worked on that were released into the world at one point, also.
However, even with game engines, I have spoken with AAA developers who have worked with both Unity and Unreal and they all say the same thing. Game engines are a lot like programming languages in the sense that once you learn truly learn how one works, picking up a new one isn't that difficult.