There's not a lot of research on how a frozen starter that is re-established compares to the original, though being able to rebuild a lost starter is the point of the Puratos Sourdough Library, where they keep sourdough samples frozen (including a portion in liquid nitrogen, I think.)
Prof. Michael Ganzle's writings, though, seem to support the concept that a starter is largely a product of its feeding and handling, ie, how often you feed it, what you feed it with and how it is stored in between feedings. His research suggests that regardless of where a starter is (US, Europe, Africa, Asia) starters that are maintained using similar processes are remarkably similar in terms of their microbiological makeup, ie, what strains of yeast and bacteria wind up dominating the culture. (Refrigerating vs room temperature seems to be one of the key differences, and IMHO is the primary difference between a commercial bakery's sourdough starter and most home sourdough starters.)
If that is true, then whether you re-establish a frozen or dried starter, or one that got lost in the back of the fridge, get some starter from another baker or start from scratch, you're likely to end up in a similar place in 6 months to a year. And that's not a bad thing if you have a sourdough starter you're used to maintaining and using.
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