Probably, but as long as they continue to provide the overwhelming majority of my business traffic I couldn't care less.
What are the alternatives? Bing is owed by Microsoft, now they definitely are a company with too much power, double the revenue of Google. Yahoo! are also a major corp.
So no, not really, not if they are holding market share away from Gates & Co.
Bing and Yahoo have their own formulas for ranking, and SEO differs slightly accordingly. If what Google says becomes law, then Yahoo and Bing must be copying them.