Calling others child while being a child makes no sense.
Not playing the game currently doesn't mean that people can't check news or even comment on whatever news they want about a game that they're just taking a break. There is also nothing happening in the game that makes the experience of any 8.3 player invalid.
And yes, at the end of Shadowlands, it will be a waste of time to farm things for Shadowlands. Nothing wrong with that.
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Why not? You can farm faster than you think and you would be able to buy whatever you want anytime you want as soon as you had the required amount of currency instead of waiting for the corruption to show up again at the vendor.
Rotation isn't there to help you.