From that page I can see that they created their own deep learning framework, their own AI conversational agents, their own data science platform, their own geospatial indexing system, their own web applications framework, etc. The list seems to go on and on and on.

Essentially they seem to be repeating whatever Google and Facebook are doing: but those are pure technology companies that serve two orders of magnitude more customers and have contributed building the web as we know it. Uber is a taxi company.

Only if you want to have a huge and complex system. If you have small and localized ones, it should be very cheap.

> Uber as a product is very technologically complex, mainly because of the scale it operates at.

Also because when Uber was young, it was not motivated to seek profits or consider expenses, it was just growth at any cost. Once that work culture is established, it can be hard to shake.