It takes a hell of a lot of effort to release a textbook - time to (conceptually) design it, write it, edit it, have other professors edit it, etc. In the time it takes to do that, they could have banged out a few interesting papers to present at a conference.
As for advancing in tenure-track, I doubt it. As illogical as it is, tenure-track positioning is generally related to research skill, as opposed to pedagogical interest and/or ability. Most large universities would prefer to have great researchers (who publish works with the schools' name on them) who teach as needed and without passion, as opposed to the other way around.
As for advancing in tenure-track, I doubt it. As illogical as it is, tenure-track positioning is generally related to research skill, as opposed to pedagogical interest and/or ability. Most large universities would prefer to have great researchers (who publish works with the schools' name on them) who teach as needed and without passion, as opposed to the other way around.