Resurrection Protocols

The X-Men's new jet, the Thunderbird, is named for Proudstar to honor his sacrifice, and I saw somewhere that he couldn't be revived, but how come that's the case? Why can't Thunderbird be brought back like the rest of mutantkind?

I was wondering if anyone would objected to my (or anyone else) creating a page that list any mutant that was resurrected by the Five? It could be beneficial (besides reading the Resurrection Protocols page) to browsing,