Earn it how though?
Through challengeless farming?
How is that superior to buying it?
You don't get max level conduits by doing anything but mythic raiding and I would argue class passives shouldn't be rolled into mythic sire kills or months of dailies. If they were crafted they would even have the added bonus of giving crafters something else to make.
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There is a stark difference between doing something interesting like "glory or the". mage tower, mythic plus and raiding and doing mindless dailies for a month. The fact you compare the two like they are even close to the same thing...well it reflects certain things about you.