Let's say we learned how to unfreeze people but there's no effective immortality in sight (through uploading or biohacking or anything else)

I don't think this is realistic. About the only two plausible ways I can think of reviving a cryonics patient are brain uploading and some of the more optimistic projections for nanotechnology, either of which should be sufficient for effective immortality. If there is another proposed method of revival which would not facilitate effective immortality, I am not aware of it.