I would replace the yeast and KMS and make one, as long as you still have the fermenter. Not much to lose at this point. Anyone who makes wine kits would be hesitant to purchase a 7 year old kit. Why dump it when it may just give you a drinkable result for very little investment. Your call, but that is what I would do.
I personally would make a port out of it - use 1 gallon less water and see how it tastes ? You may need to add alcohol to it - all depending on the out come.
This is what I did with an extremely old kit that was given to me.
I agree with Roger80465
selling a 7yr old kit isn't very likely... and dumping it seems like a waste. get a new yeast pack for a buck and let r rip...
the worse that can happen is that you'll end up dumping it in 6 weeks.... but it might turn out very drinkable..
The must should be sterile so i'm guessing it would probably turn out alright