Rob Gilbert is a counter example. He famously designed SCUMM and then made amazing games with it.

> I couldn’t be both a successful programming language designer and a successful game developer

Why not? Jonathan Blow seems to be making a pretty good run at it.

Yeah going very deep on specific field for 5-10 years and then hopping next thing is pretty doable.

Yes! You shouldn't try to do them both at once. But while life is short, it isn't that short.

See also this webcomic:

https://www.smbc-comics.com/comic/2012-09-02

King without a land?

I think everyone wrestles with this a little bit.

Should you really dig in and focus on mobile, web, server, game, firmware? If so, should you focus on one language?

I don't so much question paths in my life as I feel very lucky to have ended up where I am. I do question on a daily basis, whether I should stop learning and adopting new technologies, and focus on ONE domain for the rest of my life.

It seems I am destined to be a jack of all trades, master of none, if I let life continue to unfold as it has over the last 10 years, bumping around as needed from my employers to new or different domains.

There's probably an analogy here in cost of task switching. Switch too much and one finds themselves with too many tasks and too little time. Switch too little and the doings or learnings may become monotonous. As with most things good, it takes skill to play it well.

Given some games have their own scripting systems and languages I’m not sure if that’s all so true!

Maybe, but you could be a successful programming language designer and a hobbyist game developer. Depends how you define success. Making money at games is something very few do, but many have fun just for the creative outlet.

I consider 'generalist' to be a speciality, though I might be a bit odd.