Amazon was never a profit machine. I do think that's part of the core business, re-invest everything and more... and they turned into a giant comparable to Walmart.
Those companies are means to an end, not profit-generating machines.
The only real difference is that they have higher bootstrapping costs due to the type of product they make. i.e a physical object with a complex production pipeline. The only way to ever get profitable is to heavily and intentionally reinvest in R&D. Musk is doing the only thing that a startup in this space can do and expect to succeed outside of getting acquired which would be pretty much directly counter to the stated goals of the company.
How is this not investing in their future?