Developers are new factory workers. Pay is good now because industry is expanding and there's not enough of us but it won't be like that forever. And bottom line work is already being commoditized (WordPress ecosystem etc).
The entire idea of a factory worker is that they can be swapped in place by another and the output is maintained to a great extent. This just simply isn't the case in software or really any creative work. Even if we assume two workers have equal skill sets, something that is already dubious due to the importance of cross-domain knowledge in software, the personality one brings to a team will ultimately alter the entire team, sometimes good, sometimes not so. The social dynamic within groups is a critical element and something that cannot be commoditized away like other professions.
As to the point on commoditization within old tech, I can only answer with a "well duh, It's tech!". The goalposts are always moving within this profession. There used to be a whole heck of a lot of jobs in programming super low-level tasks, those are largely gone and have been replaced with new positions. Last year everyone worked on web apps, this year everyone was on mobile apps, next year it's anybody's guess.
I spend a lot of time within WordPress ecosystem and I've seen people coming to me with 20K products shops they've built and maintain without a single line of code written.
I've seen companies operating online without having any developments either on contract or in house.
Because for certain simpler scenarios, there's UI based tools you can run your business on.
Sure they come to me because eventually they need something they can't do with tools they use but those are becoming more and more high level jobs.
Web development is pretty much figured out problem. You have legions of repleacable low value developers churning out pages and you have subset of highly paid specialists who can do more advanced things.
But those gazillions web pages are doing their job, they drive sales, improving information quality etc. so I could say digital workers are factory workers of our time.
On certain jobs line is blurry - designers can do basic WordPress but they also can set up MailChimp because machine needs to be humming.
I think developers will still make good money for decades. I could, however, see an issue with junior developers finding less opportunities in the coming decade. I think there will be less need for juniors and the entry level jobs will be harder to come by. Some of those skills are more easily "commoditized."