As far as I understand Amazon makes a deliberate choice to reinvest their profit into research, marketing, etc, with the promise that it will grow more in the future.
Musk has been very upfront that Twitter is bleeding money (hence why he is firing so many people), it's not simply that a healthy profit margin is being reinvested.
Musk has been very upfront that Twitter is bleeding money (hence why he is firing so many people), it's not simply that a healthy profit margin is being reinvested.