I guess I don't understand that kind of objection.
Imagine an island. There are 100 people on it. Ten people farm, and provide sufficient food for 150 people.
Thirty people make necessary things, each with spare capacity to make things for 150 people. Shelter, furniture, household goods, etc..
Another 20 provide various services, enough for an island with 150 people on it.
Assuming 30 are children, this leaves ten people today who have no work to do... unless they invent new good or services. Not necessities - necessities are already covered. So they need to find something that makes people happy, that people will trade for. And they'd better get cracking; those 30 children are growing up, and they'll need something to do, too. And it's going to take a good many years before they can get jobs as farmers or manufacturers of necessities.
At some point in time, on this island we call the earth, we're going to run into similar problems, unless we overpopulate to the point that we *can't* produce food and necessities for everyone (a real possibility, though it's hard to say what the Malthusian limit is; as wcg
has pointed out, each person born is not just another mouth to feed, but another brain working to figure out better ways of feeding, clothing, housing, etc., everyone.)
The more new and interesting products that are invented, the bigger the overall economy is, and the more money flows. If there weren't espresso machines, and people who wanted to buy them, the overall economy would be smaller; there'd be less money flowing, and fewer jobs for those who wanted them. (Unless some other new product filled the gap.)
Just as important, the market for these things makes life more interesting. You have been known to go to opera; if there was not a market for that, you would never have the opportunity to do so, and no one would have the opportunity to learn of a new-to-them, wonderful thing. Similarly, without espresso machines, no one would ever be astounded at this tiny miracle of physics and chemistry that turns ordinary coffee beans into something that they hadn't ever imagined before.