Because Google routinely undermines their partners through internal productizing (see e.g. Flintstone/OnHub), and Google has a large self-driving car program. There's a clear path from there to a Google(/Alphabet)-owned ride provider regardless of investment in Uber.

Uber is building out their own map system so that they are no longer dependent upon a third party. It's already in production on a limited basis.

Isn't Google Ventures pretty isolated from Google?

Uber bought Bing Maps for $1.

This just isn't true in any way. Uber once upon a time was a bidder on Here Maps, which provided most of Bing's mapping data, but they lost to a consortium of German car makers (BMW, Daimler, Audi): http://www.wsj.com/articles/bmw-daimler-audi-agree-to-buy-no...

They acquired part of Bing's Mapping Assets alongside ~100 employees - http://techcrunch.com/2015/06/29/uber-acquires-part-of-bings... and http://www.wsj.com/articles/SB110643412133885342696045810783...

you mean $1B surely?

No. I can't name a source though. Basically Microsoft was hemmoraghing money on this unit and Uber took a chunk of staff, the tech, AND the operating expenses.

$1 doesn't make any sense. Perhaps you're leaving out some form of equity swap. Bankrupt companies get purchased all the time for millions of dollars and I can't imagine Microsoft's business team would allow such a shitty deal.

Bankrupt companies also routinely get purchased for $1, with the old owners just glad to get rid of outstanding liabilities.

It only makes sense if the unit was hemorrhaging money and had near iron clad contracts/termination penalties.

Google has the map data. Google are working on autonomous vehicles. When they get the latter, what is the need for Uber? The $250M would be an irrelevant sunk cost at that point.