Why does the percent of income matter? Whether its 1% or 100% Microsoft had zero problem paying to take Google's place as the default search.

The contrast between Mozilla and Apple is that one needs the money and the other one doesn't, and that makes all the difference.

Apple can pick and choose their deals. If Apple decided to give Microsoft the search box for free to spite Google they could do it in a second.

Mozilla is completely dependent on monetizing the search box. I think at $100 million per year, Microsoft was interested in bidding for Mozilla's search box. At $300 million, it was untenable.

Mozilla being reliant on the search box and being reliant on Google are two different conversations.