mgm was also losing money, which also had a hand in sgu/sga cancellation. SGU writers/showrunners realized thier mistakes too late, season 2 was getting interesting. and allegedly in an interview season 3 was including more of the aliens"threat) that have been missing for almost 2 seasons. the planet builders was suppose to be part of season 3. years later i heard they said, they couldnt reboot or make a new SG series because of current “societal issues” i got this from various posts on reddit over the years.