I don’t think this is true in general.
That is indeed true for many kinds of bridges, such as for lock+mint and lock+unlock bridges, the locked SOV would indeed have a claim to be the “real” token as you say. But your claim does not apply to all types of bridges. In particular, in the case of a burn+issue bridge, I don’t think it’s true that the “real” token remains on Rootstock, as SOV on Rootstock gets burned, and only complete destruction of the rSOV creates SOV over at the other chain (compare teleburning NFTs from ethereum to bitcoin, original NFT destroyed → Ordinal on Bitcoin issued).