Hey Dude,
I said that they test and select them. The same IC but a wide range in performance. Since they are the same price, OOOps I just checked Newarkinone. The crappy TL082CP made by TI costs more than the low-noise TL072CP also made by TI. Go figure. They are duals and both cost less than the single opamp, TL071CP and TL081CP made by TI which have an identical price. Go figure again.
Maybe they started with the TL081, and many projects used it. They went on to make the dual TL082 and the quad TL084. Then they found out that some of them had low noise so they sold those as TL071, TL072 and TL074. The "sevens" became very popular in audio equipment and their price dropped to be the same or lower than the crappy "eights". They still have rejects so sell them as "eights". I don't want rejects, do you?
You know what? Maybe the only difference is that TL08x are not tested for noise if they have lots of low noise ones in stock.