Why is that? and what are the two approaches?
Tesla, on the other hand, is trying to make their cars work anywhere. It's a larger problem space, but the end goal is a far more robust product, with much lower long-term infrastructure spending.
I personally like the robust approach, but I think both approaches are long-term viable, albeit for different use-cases.
You on the other hand, have no explanation whatsoever as to why you think a non-HD map system is robust everywhere compared to a HD map system. If you claim that HD maps are less robust by definition, you clearly do not understand deep learning or computer vision.