I totally share your concern, but I think there's reason for hope assuming it's not Terminator-style AGI that destroys the world (bigger problems than unemployment in that case). Specific to your scenario, it seems like companies are laying people off today in the name of AI efficiency gains (that in itself is debatable, but let's assume that is why they're doing it--they think they can do the same if not more with less). But if you play out those same efficiency gains companies that are in growth mode ought to be able to use those efficiency gains to accelerate product development. So instead of laying people off, companies will be able to build product that much faster because their employees, and engineers in particular, can move so much more quickly. We're so early, though, and c-suite folks are so myopic that the troops haven't yet had time to show them that revenue growth is the real prize of AI/LLM's (and believe me it's always the some troops that show them the way).

On a larger level, I would just ask your fictitious medium-level engineer what are they able to do today, with an AI/LLM, that they were unable to do before? As a very basic example, and one that is already true with existing LLM's, a mid-level engineer who wanted to build an app might've formerly struggled with building a UI for their app. Now, sans designer, a mid-level engineer can spin up an app UI much more quickly, and without the labor of finding and actually paying a designer. That's not to say there's no value left in design, but if you're starting out it's similar to how bootstrap (dating myself here) was an enabler because you were no longer in need of a designer to build a website (was still a huge time suck and pain in the ass though). You can multiple that by a bunch of roles and tasks today because LLM's make it possible to do things you just formerly wouldn't have been able to do on your own.

Last thing is the much more high level. Every time some new tech is introduced there's a lot of concern about displacement. I think, again, that's valid and perhaps moreso with AI. But it does seem to me like major new tech always seems to create a lot of opportunity. It might not be for the exact same people like your mid-level engineer (although I think it might for him/her), but I stay hopeful that the amount of opportunity created will offset the amount of suffering it will cause. And I don't say that in some kind of "suffering is ok" way, but just like revenue growth is the be all end all for so many companies, tech brings change and some suffering is a part of that. Prior skills become less important, new skills are preferred. Some folks adapt. Others thrive. Some are left behind.

If you're still checking in on this thread, and you actually read my diatribe, do you think I'm totally full of it? Again, I don't know that I would bet it would work out this way. Actually I probably would bet on that. But I'm definitely hopeful it will.