If it wasn't google paying, it would be microsoft, with bing.
It would be a huge loss for Google currently. Don't doubt for a second that if Firefox marketshare falls under 5% Google will stop paying anything.
http://www.zdnet.com/opera-google-extend-search-deal-for-two...
Opera makes about $15M per quarter in revenue from its desktop browser:
http://www.favbrowser.com/opera-software-q2-2012-financial-r...
Even Opera's marketshare is significant.
But just imagine, for a second, that 20% of the internet just gets to use bing instead of google.com because it became the default overnight. Outch.
If it wasn't google paying, it would be microsoft, with bing.
It would be a huge loss for Google currently. Don't doubt for a second that if Firefox marketshare falls under 5% Google will stop paying anything.