Halfway joking here but I think perfectly ordinary people who just use a few tabs at a time tends to just use whatever thay get their hands on, -IE on Windows or Safari on Mac.

This means there is already a bias here: Those who use FF use it anyway because there is no alternative that has Scrapbook extension (offline browsing w/searchability), tree tabs (for automatic mind mapping) that also handles 100-200 tabs in a good way. (Read up on David Allen on using your memory for real work not to remember addresses and tasks for why some people find this useful.)