It may not be the case that services are the end game, but rather that there is a trade-off due to organizational structure and capital investments needed to sustain a product-focused company vs. a service one. As revenues from one type of model dry up (e.g., majority of people have your product), the investments needed to sustain that type of company structure have less marginal value or may even be a drain. Simply put, there are always diminishing returns to any strategy and there may exist a middle ground that maximizes revenue.

Related to topic, Professor Cusumano at MIT wrote a good paper covering this exact topic back in 2008 which covers additional historical cases dating back to the 90's. A lot of what is happening now follows logically from that analysis.

I couldn't find a direct link since it was an IEEE paper (pay to access), but found a copy here (if bored, skip to page 6 on the pdf): http://www.iae.univ-lille1.fr/SitesProjets/bmcommunity/Resea...