In contrast, the production cost of a bitcoin tends to move toward its price because the price acts as a ceiling and competition drives the production cost to the ceiling by changing the difficulty.
Thus, the price of a commodity may ultimately depend on the production cost, but the price of a bitcoin does not. Instead, the production cost of a bitcoin ultimately depends on its price.
after all if every man and his dog could cpu mine bitcoin at an average of 1cent per btc cost. do you really think the markets will be at $28k speculation today.. nope every man and his dog would be selling down the market to correct the price down to cpu mining cost with only a small profit margin of speculation.
no one would even dare want to buy bitcoin for $28k if they could self mine for 1 cent
its called economics, common sense, logic
If you assumed that the mining cost would somehow stay at 1 cent per BTC, still only 6.25 BTC per 10 minutes would be available at that price. Total trade volume is 1000's of times that. Only a tiny fraction of people could get that price and the rest would have to pay full price.
But, the mining cost would
not stay at that price. Like you said, every man and his dog would mine BTC if the production cost were that low, and the result would be a swift rise in the difficulty, and thus production cost. So, whatever affect of production cost on price would be temporary at best.