Post scarcity doesn't strictly mean that it's just robots that do everything or it's all automated, it's more that people no longer need to work to live (or rather to live well). It's not that nobody will ever work, you can still have people working, but the fact that they're working would be voluntary. A person may work at a daycare because they like kids and want to buy some luxury, not because they'll be eating out of trashcans if they don't.
You also have to keep in mind that a good deal of the US economy is currently a fairly ridiculous circle jerk of service niches that can only be profitable in an environment of subsidies and low wages. And even then, labor is typically their highest expense.
Fast food is a good example... nobody would starve if every fast food joint in the country were closed, because their role is strictly about service and not food (well, the workers may starve, since they're already living in poverty). What they're providing is a place where you can buy pennies worth of crappy government subsidized food prepared by minimum wage workers (who are either in poverty, working 60 hours a week in multiple jobs, or dependents on someone else) without having to cook it yourself or wait 10-20 minutes. And hey, places like this can exist and make money. Are there better (more efficient, healthier, less labor intensive, less wasteful) ways of distributing food? Of course there are. But that method happens to be the most profitable, convenient, and marketable, so even though the food could be practically free people continue to pay 6 bucks for a shitty sandwich and drink as though they're getting a good deal. And then some of that 6 bucks (after the shareholder's cut and taxes to pay for all the wars that nobody seems to be aware of anyway) goes to pay the pathetic wages of the workers, who get to continue living. What a bargain.
And for as long as we live in this kind of an economic system, the emphasis will be on creating jobs! Creating new markets! Helping businesses employ more people! While actually, the reality is that these jobs are pointless economic stopgaps that conveniently fill a void where workers need to be doing something to live while the real economic heavy lifting (that makes everything of any importance possible) comes from near-slave labor overseas and militaristic protectionism of international markets dominated by US companies. The same can be said about most of the consumer tech industry, the financial industry, half the construction industry, the agricultural industries (specifically livestock feed and corn syrup production), and many others, each with their own flavor of madness. They're just building off each other on top of the already present foundation that most of our needs are met, and have been for half a century, and all that's left to keep the system going is consumerism, war, and political inertia propped up by those most profiting from it.