I would replace "own" with "control". They don't hoard production facilities and buildings in their locked cellar. The things they own are still being used to produce stuff consumed by other people than the owner.
No, but they control the economy. They decide what projects to start, and since they are so rich they only think in hundreds of millions at least. So we get less local control - which are all small projects - and more mega-projects/corporations. Which are better at producing at scale, but are (much) worse at providing a satisfying work environment. So we end up producing more than enough stuff, but much of it not actually needed - here you need clever marketing to convince people to consume stuff they don't need, from drugs to insurance to a new shiny car.
I think much of the discussion and the picture a lot of people have in their heads about "the 0.1%" is Scrooge McDuck, with all the money right there only for himself to even see. But in reality capitalist ownership is more a matter of control of what, where, how.
Apart from the means of production, the "body" of the economy, they also control a large share of the "blood" of the economy, the money. Wherever that flow is directed things grow, where it doesn't go lights go out.
While the rest of the population still has quite a bit of money taken together, there is another problem of psychology: Money is no problem for a rich capitalist. They can easily finance billions. But for the people who don't have such easy access to the streams of finance money is much more static, money is much more valuable for the majority of people. Also, "credit" has different meanings for someone investing in a small venture and a billionaire: The latter has financial instruments so that he ends up carrying little to none of the risk.