I agree with every word Paul has just said, and also with what UK Mas says about it being your choice.
Cars are property, not children, and if a given owner does not want to make an investment into a car for the long term that's an entirely personal matter. The scrappage rate is high on these cars over the last couple of years, and will continue to be so over the next couple of years as this sort of issue comes up and people decide they can't justify spending the money. It's not an issue unique to Porsches - this is what happens to every make of mass-produced old car, which is why the roads are no longer populated by rear-drive Escorts, Capris and Sierras.
Against that, within a few years there will be three kinds of 944s. The majority will be in scrapyards. Of the surviving minority, there will be those that have had substantial restoration efforts, and those that need them. (There may also be a tiny handful of cars that have never corroded due to luck, excellent storage conditions and minimal use in poor weather, but really only a handful). I think most owners who reach the moment of truth will choose to scrap them and that's entirely their business.
The cars tend to change hands for very little money at the moment and (for now) it is possible that you might be able to pick up one that has had the necessary work done for less than it will cost to repair yours.
I'm one of those who is putting his money where his mouth is, and fortunate enough that I can afford to. I am going through an 18 month mechanical, structural and cosmetic restoration programme that by the end of the summer will see my car owing me multiples of what it would fetch in today's market. But it won't be for sale, so no-one else will be buying that one for a song. The amount of money it would take me to part with it is a lot more than anyone would be likely to offer. That suits me just fine because I intend to run it for 10 to 15 years.
A lot of people would say it's stupid to spend a lot of money on a relatively worthless old car, but all I can say to that is that it's going to be a sight cheaper to get the work done now, before the rot spreads, and while parts are readily available, than it will be in five years, never mind ten years. It's not about saying a car should never be scrapped - I am quite grateful that so many are being scrapped, as that process is creating availability of good and restorable spare parts at low prices.It's about securing the car I want to own and drive for the long term, and knowing exactly what has been done to it, and to what standards.