I'm surprised FireWire port repair is that difficult/expensive. Can't be that much to it, you just need to source the same/similar controller from another (much cheaper!) device, no?
Sure, I get that you might be squeamish about opening up a $16,000 device yourself and taking a soldering iron to it, but a port/connector is about as low risk as it gets when you need to repair electronics.
If you don't have a decent soldering iron or any of the related accessories, this "$3k" repair will cost under $100. If you do have one, it will cost you under $10.
It's a niche market, and they're just taking advantage of such niche market, however morally gray it may be.