Not really sure what this article is trying to achieve, but if it's trying to say that fpgas can replace legacy systems that may be end of life..
That may be the case in the event that the legacy system consists of hardware that is no longer manufactured, and doesn't have a modern equivalent. But the costs of implementing (including testing) something like that using FPGAs may mean it's actually cheaper to replace the entire system.
I have limited knowledge of FPGAs, and have never programmed one. However, my understanding is they are frequently used in low manufacturing run PCBs, and often for prototyping designs that will ultimately be implemented using other means.
Much as I like the Spectrum Next (in fact, I'm considering buying one to mess around on), I think that is a good example of a PCB with a low manufacturing run (likely to be a few thousand, rather than the millions an xbox or PlayStation would require..