I feel some "commoditize your complements" (Spolsky) vibes hearing about these acquisitions. Or, potentially, "control your complements"?

If you find your popular, expensive tool leans heavily upon third party tools, it doesn't seem a crazy idea to purchase them for peanuts (compared to your overall worth) to both optimize your tool to use them better and, maybe, reduce the efficacy of how your competitors use them (like changing the API over time, controlling the feature roadmap, etc.) Or maybe I'm being paranoid :-)