I'm not convinced anything you could study today has better than a 50% chance of still being viable in 20 years, considering how rapidly the economic, social, political and technological landscape is changing.
Even in the Age of Chaos (that's already begun), there will still be things that need to be done that people will pay for (even if the pay is not in the form of money).
Possessing knowledge, skill, and/or experience involving shelter, water, fire, and food will always be handy so long as there are any humans left alive on this planet, so knowing how to build 'shelter,' how to purify/clean/manage water, how to acquire/store/utilize energy, or how to grow/acquire/distribute food will always be relevant (to say the least!). This can be approached in a high-tech manner, a low-tech manner, or some combo of both.
A friend of mine moved to Romania with her husband a few years ago and started a teaching farm where they hold classes in organic farming, canning, livestock management and all the rest (mostly old-school farming/homesteading skills) and so far have never failed to sell out every single class they've offered. The vast majority of their clients are Western Europeans who live in big cities, rarely walk on unpaved surfaces, and who have an innate desire/longing to get their hands into some soil (to basically cure their raging case of "nature deficit syndrome").
So there are legions of individuals (here and in Europe) who are ready, willing, and able to fork over a lot of money to have their sterile, urban lives infused with a bit of dirty-fingernail authenticity. And maybe even get a blister or develop some calluses to show off back at the office, lol. My friends also do no advertising at all since word-of-mouth is all the marketing they need. Lots of people are starving for this kind of experience, even if they don't fully realize it yet (they often start to when their co-workers return with the Slackful afterglow of having had a truly genuine and inspiring experience for a change).
I'm all about this kind of thing, and as a matter of fact I just signed a contract with a land owner (as in last week!) wherein I will be developing a very similar program for his place once I've relocated to the property (which includes ~200 acres bordering a 2000 ac. State Park to play in). The land even sent me what I took as a positive sign while I was checking it out in the form of armloads of giant yellow morels in perfect condition that popped up last Saturday (I've never had a haul like that before and didn't even explore a fraction of the land!).
When thinking about making a big change in life, IMO it's best to 'feel' our way towards something that truly draws us in a way that's deeper/more meaningful than just the possibility of a decent paycheck. And one must be prepared to accept the necessary compromises that such a change requires; for example where I'm heading there's no cell coverage yet, which I can live with no problem but others might not be able to accept that. It'll also be a 90-minute drive to the nearest Trader Joe's and 20 minutes to the nearest anything at all, which again is fine by me but wouldn't be for everyone. So "Know Thyself" (easier said than done) and act accordingly. A line from a Leonard Cohen song (Democracy) comes to mind (and serves as a kind of warning):
if you know what I mean;
I love the country
but I can't stand the scene...
So don't move on out to the country before realizing you'd rather live closer to the amenities of a city with its nice restaurants, concerts, shops, museums, airports, Trader Joes', and all the rest. Likewise, don't stick around in a city and try to make a go of it in one if you feel drawn to live closer to the Earth and without the noise, pollution, crowds, and all the rest of not-so-nice stuff one must deal with in densely-populated built environments.
We all have to make our Great Compromise (or it will be made for us, which we probably won't like). And time ain't our friend, so...