Question

Although many artists continue to create into late adulthood, those who do tend to believe that their work is of lower quality than when they were younger

Answer 1

That statement is false.

On average, people obtain a sense of humbleness as we got more mature.
This is also true among artists. Younger/new artists tend to feel that they're artworks are a break through and should be used as a new standard even if their skill is still unpolished.