The case for new ideas must be made. We must have those who will push the envelopes of society. Who will venture into unknown space. Who challenge the conventional, not simply because something is conventional, but because they know (or at least think) that another way is better.
This is how society gets better. “Cultural entrepreneurs” engage in and create the market of ideas. A sea of thoughts within which humanity swims.
Their function is much like entrepreneurs in the realm of production: individuals who refuse to take the existing technology or market structure as given and try to change it and, of course, benefit personally in the process. Much like other entrepreneurs, the vast bulk of them make fairly marginal changes in our cultural menus, but a few stand out as having affected them in substantial and palpable ways.