Every company has a different acquisition strategy. In the 1990s, Symantec seemed to buy any company that would say yes. The result was a company with system repair tools, security software, compilers and various sundry utilities.
Other companies, like Microsoft and Apple, perform small, strategic acquisitions of companies that give them what comes down to a component or a piece of the larger puzzle. When Microsoft makes those strategic purchases, it has paid off handsomely. Although you might not realize it, some of Microsoft's most-used products were bought out.