Well, the biggest strength for Microsoft as a company is as supplier to other companies who actually make and/or market big ticket hardware. Almost without exception, when they moved out of that market, be it with the Zune, Surface (Pro), or Microsoft Phone, they turned potential customers into competitors. Compare this to Google, who did and does do phones and tablets under the Nexus line, but contracts out construction of them to the likes of Motorola, Foxconn, Huawei, Samsung, and Onkyo, and the phones' specifications are always midrange at best, so that even when Google wins, the low bidding contractor wins, too. The sole exception is the X-Box, and only because 3DO and Steamboxes proved the traditional Microsoft business model wouldn't work with consoles.
If Microsoft bought the VAIO name and the factory floorspace to build them, and if Sony was willing to sell them to Microsoft at a price that wouldn't break the bank at a time when hard feelings over the X-Box 360/ PlayStation 3 wars were at their hieght, then even if they didn't specifically market any part of the line as gaming laptops, it would utterly poison Microsoft's relations with the likes of Acer, Asus, AOC, Gigabyte, Razer, Cyberpower PC, IBuyPower, Digital Storm, AVA Direct, and Sager, let alone business and lifestyle computer companies like Dell, Compaq, Lenovo, and EMachines. This will probably push them to make bigger-up front financial commitments to the AMD K15 architecture (so that it actually happens alongside Zen) and a stable, standardized P.C. Linux distribution.