I largely agree that gradual replacement has the far better claim to preservation of identity. I would have hardly any desire to be uploaded any other way.

However, the car of Theseus example allows for a worrisome wrinkle. What if you kept all the old parts during the process you describe, and then after, you re-assembled them? Which car has the superior claim to being identical with the old car? I think it obvious that the reassembled old parts have the superior claim over the car produced by part-by-part substitution of new parts.