It is a numbers game. You most likely don't have the numbers that they play with. A 440 lb steer they will put on 1,000 lb making it 1,440 lb. Fat steers were reported at $2.56 this week. That is $3,686. Minus the $2662 is $1,024 to add 1,000 lbs. It cost them about $0.80 per lb for the gain. Strictly on the cost of gain they are $224 to the good. A 440 lb steer is likely going to some cheap grass to put on 300 lbs or so.
Also what you consider a decent profit. $100 a head is probably not worth your time. But for those running 10,000 head a $100 a head profit works out to be a million dollars.