27" iMac Firewire Port fails after 300 days of use

Question

I had to take my 27" iMac (purchased in 2012) to the "Genius" bar today because the firewire port failed.
Prior to this:
My Apogee Duet Firewire Sound Interface has given me all kinds of errors with the iMac. I wrote emails to Apogee complaining about the Firewire issues and they gave me a long list of possible fixes, all of which did absolutely nothing. Apogee claims that the problem is Apple's, but when I connected a MOTU Traveler to the firewire port it performed flawlessly. Many people had complained online about the awful performance of the Firewire Duet with Lion OSX so I wrote back to Apogee demanding that they replace the device with their newer USB "Duet 2" and they chose to ignore my email. So I went back to dealing with the intermittent cutting out of the Duet which is only remedied by either restarting the machine or unplugging & reconnecting the Duet.
2 days ago:
The Apogee Duet stops working (like so many times before), so I unplug the Apogee Firewire 400-to-800 cable and this time when I reconnect, it starts rapidly blinking and clicking, so I quickly shut the iMac down. After a waiting for a few minutes I plug the Duet in and it's dead -no lights & no click. To determine if I'd just killed my Duet, I plugged it into my 2009 Macbook with a Firewire 400 cable and the Duet works. So I think.."Maybe it was the Apogee FW400/800 cable". Next day I bought a new Firewire 400/800 Cable and connected the Duet to the iMac and I still got absolutely nothing. So I booked an appointment at the Genius Bar.
Today:
The helpful gentleman there quickly discovered that the main-board needed replacement because the "newer" iMacs have all the I/O stuff attached to the motherboard. It would have cost me 800 bucks with out a warranty. While I was there, I tested my original Apogee Firewire 400/800 cable with a Macbook pro and it worked fine, ruling out the possibility that my cable could have caused the Firewire port to fail. Lastly,  I asked him to connect a Thunderbolt-to-Firewire Adapter to my iMac and - yes - the Apogee Duet worked fine through the Thunderbolt Port.
In Conclusion,
I'm glad that they are going to repair this problem but it would appear I really have no choice but to extend my "Apple Care" since, in my experience, the Firewire port can spontaneously fail. As a full-time musician it's lucky for me this happened while it was still under warranty, otherwise I probably would have just bought the Thunderbolt-to-Firewire Adapter and hope the Thunderbolt ports last longer than the firewire did.
Has anyone else had their main-board replaced due to Port Failure?

Answer 1

Not because of Firewire, but yes, my 2007 iMac had to have extensive things replaced twice under extended AppleCare.
I personally think $2,000 dollar items should come with more than a one year warranty, unless you expect them to die shortly after a year.
Didn't need any warranty on my Quadra/630, still runs every day, they don't make Macs like they used to.