Earlier quoted context omitted.
Commercial art in general has been that way for centuries. Doesn't mean that it's intrinsically devoid of quality. Many of the classical masterpieces were made to order to cater to the fancy of some rich patron.
Many? Virtually _all_, either for a rich individual or the church. An artist just making a thing, and seeing if people like it, is a pretty new invention. Probably a big part of why post-19th century art is so much more interesting and diverse; Western art pre-19th century was largely about technical competence in whatever the current fashionable style was.
I sincerely doubt if that's how it works even nowadays. You need to be discovered by a well-connected and well-heeled patron who thinks what you do can be marketed with just a few tweaks. Very seldom does the artist become the patron of their own work is my guess. Banksy might be one of the few exceptions that prove the rule.