Our profitability calculations of the 24hr actual that you see for each algo are (total mined blocks in a 24hr period equivalent to their BTC exchange rate)/(Average total hashrate of that algorithm over 24hrs). Since the denominator of the expression is not Petahashes large, it doesn't diminish the earned results that our pool collectively finds. That being said we also optimize what offerings are available based on what hashrate the pool has online. We care about how our pool is doing and how we can bring each miner a higher result at the end of the day.

Also I should mention, the entire crypto exchange rate conversion number is extremely volatile right now because of the bear market that BTC and other cryptos are experiencing. Some of the altcoins are becoming more resilient and earning more BTC per day because BTC has shrunk >35% in a week.

Finally to your point about only one coin being mined, there are dozens available on the algo but the stratum ensures it finds the most profitable and sends most of the hashrate to the highest if it exceeds a certain percentage above other options. Each day is a different story, different coins have good days and the pool adjusts to meet that.