This discussion is about EB2/green card process, not L1/H1 visa that employee is given when relocating to the US. That is why it is not obvoius. In a lot of cases, an employee works in UK (or another European) office for many years, then moves to the US on L1A visa, works there for several years, applies to green card (not with intent to stay in US forever, but because L1 visa (and H1 too) cannot be extended for more than 5/6 years). Then to get this EB2/green card document employer has to pretend that they plan to replace this person who is already working in this organization for 10 or more years. It is not specific for Apple, Intel is doing the same when a CPU architect from Haifa or fab engineer from Dublin is working in Hillsboro for several years and decide to stay for a few more years. Or google bringing someone from Zurich.