WoW Classic is set for release summer 2019. There is no exact date as of yet, but Blizzard has been consistent in saying that it will arrive at this specific period in time several time. They also made a joke about “Soon™”, and that they “really mean it this time”. The joke originates in the Blizzard fandom where community managers have used the word “soon”, which in their understanding of the word could mean anywhere between tomorrow and the end of the universe. The fact that they are so frank about this and joking around with it highly implies that they have most of the infrastructure for the game completed and are just in a polishing phase.
To gain gold in World of Warcraft, you will primarily be grinding professions which are fantastic for receiving rewards. Mining is an example of a great profession at an early-game level. While Herbalism is actually the best gathering profession, the issue is it uses consumables which can make the profession rather costly, with the investment required.