We are not talking about whether or not other search engines are probably, maybe now in a better place to compete with Google in terms of quality. Let's assume that they are, even. In fact, let's assume that they are, in fact,
better. What we are talking about is this question:
Is the default search position in Firefox for sale to the highest bidder?
If Bing today is the better search engine, or if it's slightly inferior to Google, or if your perspective is that when Bing debuted it was terrible and it's even worse today--these are all absolutely immaterial. They have no bearing on the answer to this question.