Yes and no. Certainly, newer cameras make improvements in image quality, especially in ISO performance. But those improvements are rather slow and incremental.
Take a look at the Canon Rebel XS (5 years old) versus the t4i (less than a year old) --- The XS has a maximum ISO of 1600, versus 12800 on the t4i -- Yes, that sounds like a big difference....
My camera is also capable of 12800 --- But the reality is, 95% of my shots are at 1600 or lower.
More importantly, dxomark rates the sensor image quality nearly identically between the XS and the t4i --- So at least according to dxomark --- A photo taken at ISO 800 or 1600 on the XS, will have the same amount of noise and same image quality as taken with the t4i.
So basically... comparing the old XS with the nearly new t4i -- At ISO 1600 or less, you're getting the same image quality.
But the newer camera has the "ability" to shoot at higher ISO. (But those higher ISOs won't do such a phenomenal job at noise).
You can look at the high ISO ability as a "bell and whistle" or you can look at it as meaningful image quality. Depends how you use it, how often you intend to use it.