A wild guess would be at least 8 years, 10 even but this isn't a car is it. Mines been in the garage probably rusting for the past 3 years.
To be fair you did let us down miserably as parts were like rocking horse poop 4 years ago so you do need to stock spares for longer, especially with your top of the range products or you will continue to get a bad rep for after sales and obviously lose trade due to it.
Whilst Corsair is great for in warranty stuff, you did drop the ball on this case as a prime example.
The fact it is being dragged up after 8 years is laughable though.
I wonder how long I should hang on to mine before I can make a mint parting it out :sunglasse