Anything can be restored at a price.
It's when it breaks the point of being a cost effective option, you have to start to think is it worth it.
If its cheaper to just go and buy a excellent early 911, rather than spending countless hours and probably twice as much money to restore one that's to far gone, I guess you have to ask why am I doing this.
That is unless you love projects like this and money is no option.
I had to think about this when I bought my 911T. In Australia I could by an excellent one for $40,000 AU. And to restore mine was going to cost $25,000 or more plus the cost of the car which was $20,000 AU. And that was just for the body work, no engine work.
And this was it "unrestored"