What is the difference between fishing in an open world Single player game (With multiplayer features) and an MMORPG? I think every item in the fishing activity will be inevitably reeled in but how easy the progression gets is the key difference.
Open World games tend to make parts of the game easier for the player as they progress, it's just the nature of the game and that includes gathering resources. Gathering resources becomes more efficient and more pieces of equipment ensure only the finest materials are gathered.
For fishing, it takes away the 'happenstance' of the catch. That is why the game fishing stories I share is often an MMORPG. There are some items that increase gathering potential/skill but generally it is left pretty much alone. The variety of zones and the level are the 'filter' of what can be caught and even then there is always a chance of random events happening as is the nature of an 'multiplayer' world.
I enjoy random outcomes and Open World games tend to progress to a point of 'expected results' which takes away the thrill of the fishing activity.
Maybe I am being silly for putting a 'gate' on myself and this virtual activity but that random find when casting out is what I enjoy.