Something is only "written off" if you have profits.This is a good question I’ll attempt to answer:
The rideshare companies probably know the won’t finish the race to design the ultimate SDC that everybody wants, but they have a unique advantage whereas they can raise tons of quick cash from their ants who churn vehicle-depreciation into earnings used by the tech companies to fund massive amounts of research & development that is “written off” while at the same time piling up a ton of patents that have value and can be sold off to the highest bidder.
Remember the guy who first patented “intermittent” windshield wipers? These unique patents have a lot a value that make people rich.
I made $1 but then spent $1 in R and D, means my profit was $0 and I don't pay taxes on that $1.
I cannot imagine how all these people trying to produce economically viable robot cars expect theirs to be the one.
But the patents make sense to me. Somewhere on Uber's books these are "valued".
Also, somewhere there is a "value" given for their share of ownership in Grab, Yandex, DiDi, Fair.com.
These are Uber's biggest disasters and somehow they came away with an "asset". I would be curious to see how they "value" these "assets".