The bitterly ironic thing about Korpi is his value and play has now regressed so much that he's now probably going to get a contract/role of the exact type of player/salary/term of a goalie we should be looking for in free agency: a proven veteran backup on a 1- or 2-year deal worth around $1.5-2M. So in that sense, it'd be the perfect solution to just re-sign him while Tarasov plays another year or two in the AHL (i.e., it'd be a great move to re-sign him if we were in Franchise Mode in Chel).
Unfortunately, these aren't computers/video game players. There's probably some bitterness (fair or not) on Korpi's end to CBJ, and even if he's lost his NHL starter opportunity league-wide, he'd probably prefer to try to be a backup in a different organization. And on CBJ's end, both the organization and Elvis would probably prefer a clean break to firmly establish that Elvis is "the guy". Even if you bring Korpi back in a clear "backup" role (based on what you tell him and his salary/term), there's still that lingering "battle" in recent history that wouldn't be there if you sign a guy like Halak, Jones, Rittich, Elliott, Wedgewood, etc., instead. It really doesn't make sense for either party to re-sign, even if on paper and only accounting for role, it'd be a good fit.