Why did Larry Page promote Sundar Pichai and give him most product responsibilities at Google?

Presumably, because he is talented and delivers. From what I read, Larry and Sergei want to simplify processes and reduce number of distinct execs right under them in the leadership graph, and they probably chose based on performance, merit and also on the fact he is both a products and a technology/engineering person, in terms of experience and expertise. Doubt this was factored in that decision process, but he is also a very likable person, he is young and he is good on stage.

The WSJ has obtained excerpts from the memo sent by Larry Page announcing the changes. He promoted Sundar Pichai for faster execution and because they see "eye-to-eye when it comes to product." CEO Larry Page says the 16-year-old company is showing signs of age, and Page wants to make sure it stays innovative. That’s the message from the memo he sent to employees Friday, elevating Senior Vice President Sundar Pichai to a newly established role overseeing most of the company’s key product areas. The memo was earlier reported by Re/code. Google’s new organization is “a more common corporate structure,” Page wrote. He said he hopes employees will see “faster, better decisions” from the changes. Below are excerpts from the memo, obtained by The Wall Street Journal. “As you age, even when you’re still a teenager like Google, you have to work hard to stay innovative. Innovation is messy, a disruptive process, and people tend to be more comfortable doing what they’ve always done with a few minor tweaks. … So I’m making … changes today to ensure we continue to strive for market-leading excellence and beyond in our existing already hugely successful products while also getting the next generation of big bets off the ground.” The changes effectively put Pichai in the number two spot at Google. It’s clear from the memo that Page trusts Pichai to handle most operational decisions involving Google products, while knowing when to run the most important issues by the CEO. “The technology horizon is so broad and complex today and Sundar has a tremendous ability to see what’s ahead and mobilize teams around the super important stuff. We very much see eye-to-eye when it comes to product, which makes him the perfect fit for this role.” As Google has expanded into new areas and developed new products, more people reported directly to Page. The CEO said the changes would “free me up a bit so I can focus on the bigger picture.” Page said he would work with Pichai on key products, business issues with Chief Business Officer Omid Kordestani, and oversee Google’s “newer investments in access and energy.” The product and business sides of Google’s operations will be separated further under Page’s re-organization. “In terms of management meetings, we’re going to simplify things too, taking our current main management meeting and splitting it into more focused parts. Sundar will run… product-centric meetings with real focus on excellence. I will run a more business-centric meeting with our functional leaders and Sundar, drilling into sales, partnerships and deals as well as any important legal, finance, HR, government relations or PR issues.” Kordestani will set the agenda for the new business meeting, while the roles of co-founder http://topics.wsj.com/person/B/sergey,-brin/584, CFO Patrick Pichette and Chief Legal Officer http://topics.wsj.com/person/D/david,-drummond/6335 will stay the same, Page wrote. “Our previous structure with multiple different product areas all reporting to me is relatively unorthodox. In principle that’s good because we are not a conventional company and do not intend to become one. But it’s hard to scale as many decisions ended up coming through me. Our new approach is a more common corporate structure … scalable, focused and enables fast decision making. That’s what we need right now for Google to stay innovative, maintain our velocity and build truly excellent products.” See: http://blogs.wsj.com/digits/2014/10/27/in-new-structure-google-ceo-page-aims-for-faster-better-decisions/