Could it be because the demands still the same while the supplies gets lesser and lesser?

Miners will only mine about 6.25BTC after this coming halving, they may find it not profitable at first few months I guess but then the lesser coins they sell the higher the price could be as it will turn out the system itself is hoarding the supplies while people kept buying BTC. While the price keep growing, the miners will soon find out that its going to still be profitable to mine because prices is growing.