Almost 70 million units have been sold in the U.S. between the 360 & PS3. I'd say brand awareness isn't a problem. What set the PS3 & 360 apart is that by time they passed their peaks, there weren't nearly as many potential buyers left as there were when the PS2 passed its peak. Their sales potential was getting close to exhausted, and as a result they were guaranteed to have weak post-peak legs:
You misunderstand, I am saying 360 and PS3 did fine with the PS2 pricecuts during their reign. But XB1 and PS4 late gen sales may suffer since last gen never got pricecuts. People who adopt consoles or 2nd consoles late, may never have done that with 360 and PS3 and then those people bought XB1 and PS4. Which leads to inflated early gen sales and a short tail end. Brand awareness will then suffer for next gen PS5.
Of course the dynamics of PS4 neo and NX will probably change these thoughts as well.