I open a fresh file, initialize a fresh preferences directory, and create a text object with a non-default font and color, and do "take from selection". Studying the preferences.xml file, I see information about this object only appears two places:
<eventcontext
id="text"
usecurrent="0"
gradientdrag="1"
font_sample="AaBbCcIiPpQq12369$\342\202\254\302\242?.;/()"
show_sample_in_list="1"
use_svg2="0"
style="vector-effect:none;fill:#ff00ff;stroke-width:0.99999999;stop-color:#000000;word-spacing:0px"
selcue="1" />
and
<group
id="desktop"
style="-inkscape-font-specification:'A.C.M.E. Secret Agent Normal';font-family:'A.C.M.E. Secret Agent';font-size:53.33333333px;fill:#ff00ff">
Restarting inkscape and creating a new text object, it defaults to the new color ("#ff00ff"), but not the new font. Now I exit, edit the preferences.xml, and shove the font specification into the 'style' attribute of the 'eventcontext' for "text". Restart inkscape, create new text object, now it has the non-default font.
I conclude that Inkscape never really did include font as part of the style it remembers for the text tool preferences. Whether this is by design or a bug, I do not know. Maybe the intent was only to ever work on attributes common to all tools. The end result seems quite confusing to me.