I think you maybe got it reversed? Miners create "virgin coins" in every bitcoin block. For them, the supply of "virgin coins" is abundant. But for everyone else, "virgin coins" are hard to come by. Lots of people want virgin coins but only miners have a steady supply of them. So miners can charge a premium for them. Plus, when a miner receives "tainted coins", they can use them as fees that they pay to themselves in a bunch of smaller transactions. I suspect there are ways of doing this that evade detection by chain analysts, allowing miners to effectively turn "tainted coins" back into "virgin coins" and resell them.