Who would know? The issue with Van Gogh was/ is that he exposed the process of making art for us all to see.
What is "realistic enough" anyway? Most of his painting took place in just a few years. He rejected a lot of academic training but that took time and made him less confident of his own abiilities.
As to "Starry Night" It is a nearly impossible task to render a night scene "realistically" simply because color is dependent upon light for its effect. Light at night is mostly absent and so is color. Therefore, the rendering of a night scene must be more of effect and suggestion than "documentation." he may have been fighting through that but wit everything else, who would know?
What we have by way of a miracle of sorts are the paintings themselves and they are mostly almost too painful to look at for very long, yet his brushstrokes are so sure.
