Frederick Jackson Turner claimed that the frontier made the United States unique. Among other reasons, it served as a "safety valve" for those in the East. Do you believe him to be correct?

Coming at the end of the nineteenth century, F. J. Turner's remarks in many ways confirmed the idea of the United States as anchored in the East Coast settlements of Northern European heritage. In other ways, as he emphasized the shift of the nation's center to Chicago, the Mississippi, and the Midwest in general, Turner encouraged Americans to think coast to coast.
The idea that the economic heart of the United States was in the East still largely held sway. Although the South had been opened up to industrialization by the Civil War, it still lagged behind the Northeast, where most factories had been located. The completion of the transcontinental railroad in 1869 had greatly stimulated commerce and industry nationwide. While more immigrants were arriving on the West Coast, various economic woes in Europe were swelling the numbers arriving via the Atlantic—Ellis Island opened in 1892 to process them.
Turner had in mind many of these factors. The frontier was a shifting zone, ever flexible, that would accommodate any white Americans, whether well established or newly arrived, who wanted to improve their lives. The "safety valve" it offered was a release from the tensions and anxieties of urban, industrial life. The "safety" was not for the individuals themselves but for society. Political dissatisfaction, including anarchism, strikes, and riots, was sprouting up in the cities. Turner imagined the wide open spaces of the western frontier as welcoming to the new arrivals—largely ignoring Native American occupants' pre-existing claims on the land. He argued against the idea of a closed frontier, preferring to see unlimited opportunity and somehow not acknowledging that workers' demands would move along with them to their western settlements.