I'd honestly say STEM jobs are safe. The death of US STEM jobs will be when other countries reach a similar level of education. Right now you can outsource high-education jobs, but it doesn't matter, because those people will still want industry rates or close enough. But STEM jobs aren't very extendable. You only need one team to discover the cure for cancer, you only need one team to design the next generation fighter jet. So if people across the world actually take the advice of "if you wanted to not be miserable, you should have got a ____ degree", then you have an ever growing amount of people competing to be in fields that don't grow quickly*, and... yeah. It'll be dial-a-lawyer all over again.
That's pretty far off in my opinion, like I wouldn't worry about it in our lifetimes. And even if STEM jobs spread out throughout the world, they're still going to exist in about the same numbers, and there's only so low most people would be willing to pay a worker like that. For me, the real danger is everyone else. Within 50 years (probably a LOT sooner tho, like get worried in 10), our entire logistics network could be functionally automated. Amazon has cut out the middleman for retail and walmart is moving to do exactly the same. Self-driving cars are virtually guaranteed to result in self-driving industries. A self-driving car version of Uber (presumably with internal cameras and frequent checkups to make sure no one trashes the car), could not only replace the taxi/Uber industry, it could totally revolutionize car ownership and restructure our society to buy far less cars. But that's not the biggest change, the biggest change is self driving trucks and self operating warehouses. The point is, all of the technology exists in some stage, for you to buy and recieve something off Amazon and no human is involved at any point except you. The only thing we don't have a technological solution for, oddly, is how to give the product to the customer without someone else stealing it. But even then you could have an unskilled worker sitting in the front of the truck ringing doorbells but requiring no special licenses. And the thing is, you cut out transportation and retail from our job market, and every other form of unskilled work will have such a supply of workers that you'll have low-level management working for two bucks over minimum wage. Or just minimum wage and 40 hours...
Anyway, all of that stuff might as well be a hurricane for all you and me can control it. Besides, cutting laborers out is arguably a good thing because we can all spend our time doing fun but existentially meaningless things like cutting each other's hair and playing esports. The rot that we can control (at least within ourselves and anyone that will listen to us), is the idea that having something = deserving it. Furthermore we need to adjust our idea of the economy. Americans view the economy as a system of just redistribution (redistributing money from the bad workers to the good). We need to shift our perspective to viewing the economy as a living engine that needs to be fed. Basically, in a healthy economy, we don't want people to have money. We want them to spend it. That way people are constantly motivated to work** AND people are constantly receiving the benefits of other people's work. And we want individuals to have only short term debt, even if its constantly paid off and then replaced by more short term debt.
There's only two things we actually need from the economy:
1. Money must continue to move.
2. Everyone must get what they need, and some of what they want.
We don't have 1, the economy will weaken and die. We don't have 2, the economy has failed its function. Right now in America, we have a serious deficit of both for reasons that are as cultural as they are financial. We cannot control the financial but we can shift the culture. That's why I think Bernie is so important as a milestone, because people (especially the young), supported him much more than past trends would suggest they should have. That would seem to imply that things are shifting away from the Republican mindset, hence why I think they'll have difficult with tax reform.
*no seriously, STEM fields don't. Americans call fields like engineering and computer science "fast growing" because the supply of workers is expanding so much more slowly than the demand for them. In raw numbers, the demand is still tiny and its not growing fast enough to change that.
**or... do whatever it is that makes money if we truly are automated out of the economy.