There is no mystery to it. For example Bitcoin mined    152 Blocks last 24h each one is 12.5 BTC, makes it 1900 new coins last 24h.
Miners must recoup investments and running expenses. So more or less $8,934,226.6 USD of new money has been found to pay miners and everything else associated with generating a new coin.

Dogecoin is a good example, in the early crazy days miners reward was huge and so was price thats why a total of $112,450,599 was paid to miners, but only $24,858 for the past month on average per day.

Monero paid a total  of $60,620,373 to miners (which requires new money) and on average $338,447 daily in August. (last 24h 712 Blocks, 6.54 XMR for each block)