... miners are playing this role fine

for now

I make a distinction between miners and rentals

I've often wondered whether it is possible to make a profit with mining rentals. I assumed not...
Not easily anyway
With merges and the right timing, yes it is; however, usually it costs more than it makes (that's why most that rent, do so for the "thrill" of mining).
I for one have wasted a huge amount of money for the thrill of mining. People are weird.