It kind of already is 🤷🏻‍♀️

Just do the math for yourself. Buy an Asic, pay the electric bill and get the mining reward.

Even if you make the best-faith argument and call it heating cost (which is lying to yourself in lots of cases 🤷🏻‍♀️) you'll never make the cost of the Asic worth it

Average private person mining is only here for enthusiasts out of principle. But not economic