"...Bitcoin. Is it going to see a point where mining is not profitable? Some believe that it is impossible for that to happen. The price of Bitcoin cannot go below the mining costs. "

Whoever says ^ is a NUTCASE.
As in, hypothetically lets say a rich nutcase, goes all in buying mining gear driving the price to mine 1 BTC at $10K. Just because the small percentage of coins mined from then on cost $10k doesn't mean the 16M odd coins already in existence should each now be worth $10k.

Theory says miners will be switched off and cost of mining decreases until equilibrium is reached....BUT in the crypto/BTC space, theories rarely hold - a lot of crazy things go on when a handful of whales can easily manipulate thousands of naive people who have dollar signs in their eyes.