There is no support for touch screen navigation gestures in Firefox on Windows and that is the #1 reason why I cannot switch. I use the touchscreen on laptop while browsing every day.

Touch screens on windows isn't something new. They became common around the time of the release of Windows 8 in 2012.

There is a 6 year old feature request on bugzilla. https://bugzilla.mozilla.org/show_bug.cgi?id=1443710