Final answer:
If musicians who compose for musical comedies improve with age, it challenges the passage's conceptual artist claims and supports the author's views on traditional artists. It reflects the idea that skill and impact can grow over time, which is in line with both the respect for traditional craftsmanship and the growth observed by critics.
Step-by-step explanation:
Given the premise that mainstream musicians who write songs for musical comedies improve with age, it would likely challenge the claims about conceptual artists within the passage provided. If the suggestion is that experience contributes to the quality of artwork, it might indicate that traditional musicians or artists could be seen to enhance their craft over time, which leans toward the value given to longevity and the honing of skills, aligning with the passage author's views on traditional artists.
The passage presents ideas on how various artists affect culture and seem to indicate that change and social reform come from the new language and perspectives offered by creative minds, implying a value in artists who can project visions of the future. Therefore, the scenario wherein musicians grow better with age could both support the admiration for traditional artists' craftsmanship and extend James Miller's observations on the growth and impact of artists over time.