This is great advice. The publishing industry is about profits, not quality. Recognition of great literary quality often only emerges after generations. Even Shakespeare was not recognized as a literary genius until about 200 years after his death. Ironically, he made a lot of money in his short life because his plays always sold out at the theatre he owned. Other great writers were recognized in their time and remain popular. Emily Dickinson lived her entire life in obscurity. Jane Austen made the equivalent of a few thousand dollars from her writing. Both are now universally acclaimed authors (Dickinson recently had a hit tv series about her life and poetry).
So there is no clear connection between writing quality, popularity, and profitability. Like you say, just write what you feel inspired to create. You may or not make money. You may or may not be recognized after your death. The joy is in creating.