Philosophy doesn't put food on the table, so I have no doubt that this deal was motivated by more than a desire to increase choice. But that doesn't necessarily mean that philosophy and financial strategy are in opposition, or that decisions cannot be sought which strike a balance between both (although generally I wouldn't begrudge them if they favored the latter; see my first sentence).

In any case, Mozilla is a public nonprofit and releases public financial statements every year. Even if the numbers regarding this deal aren't public now, they will be by the end of the next fiscal year.