Question

"it is sometimes hard to understand and define generic markets because"

Answer 1

Answer: different product types may compete with each other.

Explanation: this is the short gist of it anyways

Answer 2

I believe it is difficult to understand generic markets because it can be very competitive. For example, with prescription drugs, generic substitutes can be beneficial in offering a lower cost. However, when there are several generic markets competing the price will increase due to supply and demand. Generic markets themselves can also be thought of as a brand name. In grocery stores for example, we see the generic brand but it still has it's own market. Target has Market Pantry, WalMart has Great Value. Regardless of these being "generic" we still recognize them as their own brand which can make it difficult to define what is truly generic.