Social Security benefits are designed to provide successive generations of retirees with real (inflation-adjusted) retirement income commensurate with their real earnings histories. Since each generation typically earns more, on average, in real terms than the previous generation, the system's benefit formula, which calculates benefits based on workers' earnings histories, produces higher benefits, including maximum benefits, through time. Even if your own work history doesn't benefit from economy-wide real wage growth, Social Security's wage-indexing system credits your pre-age-60 earnings for economy-wide real wage growth through the year you turn age 60.
Future benefits are calculated based on earnings history and presented in today's dollars, which means they are adjusted for inflation. But your earnings history and future earnings which are the basis of your Social Security Benefit are also adjusted for each year until age 60 to keep pace with real wage growth. So your SS benefit is not just keeping pace with inflation, it's also keeping pace with the growing economic world we live in. After age 60, your benefits are adjusted each year to keep up with inflation.