Shrinking Opportunity

“This was the pang that had been sharpest during the last few years–the sense of ebbing time, of shrinking opportunity; and now he felt not so much that his last chance was going as that it was gone indeed.”
James, The Middle Years, p. 337
“Sense of ebbing time” and “shrinking opportunity”, do these phrases mean career as a writer are over or his very life. Is shrinking opportunity really the waning of his talent as a writer.
VDW/September 9, 2023/Henry James, theme, career past prime, fleeting life force