What would be fulfilling? Tons of things. I have tons of hobbies, skills, and interests that are very fulfilling. The problem is that nothing that is fulfilling pays money. Definitely not the kind of money that pays NYC rent. So here I sit.
You'll either give them money or they'll take to the streets. There's no third option -- the jobs won't materialize.
They may not be jobs as we know them. The jobs may be based on barter, and may be somewhat criminal, but people aren't just going to sit around doing nothing while they starve.
Besides, if humans have no jobs, no organization, no motivation for anything, then the AI that's replacing them has nothing to do, so why will it even continue to exist?
There's no law of nature that says "New technology makes new jobs for horses." It sounds shockingly dumb to even say this out loud. But swap "horses" for "humans" and everyone thinks it sounds about right.
A human without means to create any industry -- an ivy league pedigree (which still matters, no matter how much we'd like to believe otherwise), a VC connection, a rich uncle -- they're not going to create shit. At most, they're going to invent a product for themselves to sell that will hopefully get them out of their financial situation and into a better one. That's economics, but it's also not responsible for the massive job growth associated with industry.
On the flipside, you have the unintelligent people that make up most of the world. It's not too politically correct to point this out, but most people are pretty dumb. I'm no exception, having acted in some dumb ways myself. But if you're not capable of being smart when it counts, then you're again not going to be creating very much. Not when it comes to job growth.
So what does that leave? Ah yes, the thing we've all been dancing around. Classism. There are already three distinct castes of people: those that create jobs, those that work, and those that have no jobs. That middle class is going to dwindle as automation renders them useless. And it's naive to think that the latter caste will become the former.
I think this idea meets with so much resistance because we'd all like to believe that everything will be ok. Everything will work out, right? It always has.
Let's put it this way: Things will work out one way or another. But that "other" route is not a pleasant one.
Still I can't disagree with the essence of it. It could certainly turn into some form of feudalism, where the haves control everything and peasants work hand-to-mouth, or worse. Though that's somewhat guaranteed at some level by Malthusian logic anyway.
Though it does open the interesting paradox where if humans kill the economy by automation, then there's nobody to buy anything anymore, so there's no need to automate anything anymore, so does the economy then come right back?
So rather than a single huge mass event where automation destroys our fabric of life, we'll have swings back and forth from overautomation to overemployment. Each swing will give us a chance to re-evaluate and rebalance our priorities.
Essentially that's already happening and has already happened over the last ... couple centuries really. I guess there's a chance that the pendulum could suddenly swing so far in one direction that it's irrecoverable, but at least I don't think one can say it's inevitable.
The great depression only had about 30% unemployment, for example. That "overautomation" phase isn't something you'll want to linger in without a plan to support these people.
EDIT: For a glimpse of the future, https://www.youtube.com/watch?v=XRXr7zB5M2A is worth listening to. It's the present, actually, but the struggles are only going to increase.
And even if there ever is a plan of how to deal with all this, I can't help but think it parallels the old sci-fi short story "With Folded Hands".
semi-sequitur: From my liberal bubble, the liberal bubble light bulb buzzes over my head thinking, perhaps that whole short story is exactly what strikes conservatives to the core. It kind of makes sense. I kind of see what they mean. Granted I have no clue what that has to do with gay rights. But for a second I understood. Sympathized, even. Anyway, back to the bubble.
The whole idea of the "real world" in contrast to "everything should be free" seem more like an example of western society than reality.