KrakenInk

In Rhythm of War, Mraize says that Radiants are so Invested that they can’t leave the Rosharan system, and that this is related to the issue of getting Stormlight off-world. We see heavily Invested worldhoppers, such as Vasher and Vivenna, however, so is this not a problem for all types of Investiture? Even if this is a specifically Rosharan issue, Hoid appears on Scadrial in Mistborn Era 2, by which point he has already become a Radiant, so how was he able to get off Roshar?