The reason Apple released Boot Camp is because users were already getting Windows running on their Macs and Apple figured it was for the best if they went ahead and released a "beta" before people really started screwing up their machines.
Apple will not buy Parallels because Apple has something better in store. The agreement made in '97 between Apple and Microsoft allowed both companies access to each others technologies. Microsoft of course got all sorts of goodies for Windows but Apple got something too. In '02, just months before the agreement expired, Microsoft released Windows XP. Apple had full access to ALL of XP's API's, a set of routines that lets an application gain access to lower-level services provided by the OS. If Apple chooses to implement these API's into Leopard, you will not even need Windows (or Parallels) to run Windows applications. They will just work.
The above quote is from
this article.