In previous stories on here about Google's tendency to start stuff, shut it down arbitrarily, and compete with itself pointlessly, I recall seeing comments purporting to be from longtime Googlers saying that the reason this happens is at least in part due to Google's incentive structure. They reward people for creating "new" things, whether they're the same as something they've already got or not, and allocate very few resources for existing products that aren't already the company's bread and butter—getting put on something like Hangouts or Voice was considered to be almost a punishment detail, based on some of the comments I read, and could torpedo your chance at any kind of promotion.