The professional artists I know aren't famous. They don't persuade people. Sometimes they do what they do. Sometimes they make things they think people will like. Sometimes they make works on commission. They make a living at art, but it is something they were doing before making a living at art and had ordinary day jobs. As professionals artists their day job looks a lot like other day jobs in that they work a lot of hours and have to deal with paperwork and order supplies and collect money from customers.
The reality of the trendy art world (high-profile artists and gallery) is that good PR is the one thing an artist absolutely can't do without. Everything else is optional. Anything can be art. No physical manifestation is required.
I'm sure the artists you mention are serious and professional. There's a distinction that's sometimes drawn between the kind of conceptual/trendy work and supposedly more honest, commercial or traditional art production. It's almost always the more conservative, conventional people who make that distinction -- it's a way of dismissing more conceptual work as pretentious or elitist.
To say "unless you have already done x, you cannot do x" is a mind-bogglingly wrong perspective to take.
Many people are capable of coming up with, for example, witty, plausible conceptual art ideas. Generally they don't pursue it because only a few famous players can make a living that way. In addition, there are the dynamics of charisma to consider: a successful artist needs to sell themselves, to persuade an audience that their work has value. It generally takes a level of narcissism to achieve that. All of that hype and marketing is peripheral to the ability to actually make the work.