Final answer:
The uncle's final words to Hester express pity for her son and imply that he believes death is preferable to a life consumed by the pursuit of success.
Step-by-step explanation:
The uncle's final words to Hester, 'poor devil, he's best gone out of a life where he rides his rocking-horse to find a winner,' suggest that Hester's uncle views life as a struggle and believes that her son's obsession with the rocking-horse and finding a winner is not a healthy way to live. The uncle expresses pity for the boy and believes that death is a release from the burden of striving for success.