First there's a difference in feel and capability with screen printing than DTF. Both have a time and place. I think DTF can do a lot but it's not a 100% direct screen print replacement.
I haven't seen refurbished P600s in forever for that price. It's tough to find them for any reasonable price. Used ones are going for $1700. We bought up a bunch earlier in the year when we knew they would run out. But I have to get a return on tying up that much cash.
Support is a huge time expense for us. When someone buys a printer from us I'm now "married" to them for the life of the product. I