There are other Corpos who would pay big money for a chip like that. Evelyn's plan was simply to make money out of it and leave behind the prostitution life. Militech comes to mind for one. Or the chinese corpo, they are actually hiding Hellman after he warned Saboru.
Also discussing this doesn't address what is the punchline in the end of the game?
Yep, not really relevant
But corpos wouldn't need to buy the chip off Evelyn. They could have some victim pay for the "Save your soul" program (the version of it when you remain alive after the procedure) and get it "legally" from Arasaka. A cleaner way, it seems (if they're interested in the technology behind it, I mean).