The thing is that the bulk of the market is remarkably non-tech-savvy. If Bing became the default search engine on Firefox it wouldn't alter my searching habit

The thing is that the bulk of the market is remarkably non-tech-savvy. If Bing became the default search engine on Firefox it wouldn't alter my searching habits at all, as I'd just set it to Google instead. However for the nontechnical majority, if it still returned the results they wanted there's a good chance they'd never get around to solving the hard problem of switching default search engines.