Here's the inflation-adjusted chart - real retail sales have absolutely risen this year, just nowhere near as much as the nominal figure, and it's mostly due to higher energy prices:
Retail sales for Sep came in at 0.8% M/M and 6.3% Y/Y, but the monthly rise was buoyed by skyrocketing prices at the pump; sure enough, strip out gas and the figure was much smaller; adjust for prices across all retail sales and the increase falls to 0.1% M/M, 2.5% Y/Y: