[slededit]

For Lyft having a taxi anywhere I want one with low wait times at low cost is going to secure their success. Not new features in their app, not even latency to the data center.

There's no reason they need to be spending such crazy amounts on servers - ostensibly to allow faster iteration. A new version of their app just isn't going to move the needle. Signing up new drivers will though.

I fail to see how the benefits AWS provides are so important they need to spend such crazy amounts.

[isostatic]

They need to be seen to be doing something other than bleeding money.

Every extra driver costs them money, every lift costs them money. If they can hold out the illusion of "we know we can save money here when we've got time and have won the market", maybe it keeps the money rolling in.