Sure, just saying that’s an important dimension of farming potential. Your MM is a more limited farmer in terms of production per unit of play time than a Brute that can (1) farm actively just as fast as you and (2) make 20 mil every time you have to run an errand or watch tv 🙂
Credit where credit’s due: my fire farmers are in fact exceptionally bad at PvE because I never ever take Healing Flames because my fire farmers are intended to be fire farmers only. I’d just IO up a second build though if I actually cared to PvE with any of them. Like my Plant/Psy has a Fire Epic build with capped fire defense etc that farms as fast as you and a Psy Epic build for general play.
There’s nothing really special about being able to actively farm quickly; I have at least 9 characters that can do that efficiently like your MM, including multiple “squishy” AT’s. But passive farming income is a whole different thing blasters, doms, MM’s, controllers, etc simply can’t touch.