Bitcoin mining has a "variable" difficulty. If many are mining, the difficulty rises a lot. Any many many are mining Bitcoin. See https://www.nicehash.com/prof

Bitcoin mining has a "variable" difficulty. If many are mining, the difficulty rises a lot. Any many many are mining Bitcoin. See https://www.nicehash.com/profitability-calculator https://www.nicehash.com/profitability-calculator in order to figure out whether your investment (buy the mining equipment, pay for electricity) would be able to break even.