I don't have a BM and I am not getting one soon, so I am not on the BM wagon. I am happy doing what I do.
It takes me 5 hours to brew. That is set up, brew, and clean down. If that was for each batch fo 20L, and I was a sparky say and charged $80 an hour that time is worth $400. Lets say 20L was a months worth of brew for the house, that is a high cost on a regular basis. IMHO. I know the 15amp supply is just one cost and there may be some others, but most brewing set ups are that way anyway, but it is a one off cost. Then you have electricity costs, but if you get a $20 cheap pot, you'll also need a gas bottle, a better reg, a burner, or otherwise you have a very powerfull stove, and yes I know some people have all of this stuff already, but I didn't and it was a set up cost.
I BIAB, and here is my extras off the top of my head.
Gas Reg,
Good Burner.
Extra 9Kg bottle over the one on BBQ. must have a spare.
Some extra brass fittings to use some other burners I have.
Gas hoses.
Bags, I have a few,
Decent Rope
Two lifting Pulleys, no I am not doing a 20L batch, and I can't safely lift the bag in a tripple batch.
Lifting fixtures in the roof.
Lifting shackles.
Cubes. - independent of brewing method, but still.
Pot, no not a $20 pot. Not saying that is not the entry level, but this post is more serious if your considering parting with the cash for a BM.
Valve for the pot
Welding / fabrication cost me nothing but would cost some brewers a bit.
Refractometer independent of brewing methid but still.
Racking tube, independent of brewing method but still.
Thermometer.
Hey I know I am not stating anything new here, just that there are little extras every way you go.
I would rather build a pipe that brought water to where I need it, than carry bucketes of it everyday, even though on day one it would be easier and cheaper to carry the water by bucket.
Fear_n_loath