No, and within the case of Bitcoin, it almost hardly ever was. Until you have been one of the quite first people to mine Bitcoin, CPU mining has never been successful. The rate will change since the blockchain's average block time development changes resulting from network hashrate. Either way, https://financefeeds.com/explore-the-3-best-low-cost-cryptos-to-invest-in-february-2025-before-they-explode-act-fast/