Yes, this is in fact connected to a general problem that Nick Bostrom has pointed out, each time you try to go back from stone age tech to modern tech you use resources up that you won't have the next time. However, for purposes of actually getting back to high levels of technology rather than having a fun reality show, we've got a few advantages. One can use the remaining metal that is in all the left over objects from modern civilization (cars being one common easy source of a number of metals). Some metals are actually very difficult to extract from ore (aluminum is the primary example of this. Until the technologies for extraction were developed, it was expensive and had almost no uses) whereas the ruins of civilization will have those metals in near pure forms if one knows where to look.