Do you mean any console that didn’t win, or the best console that came in last. If the first then my favorite of a generation hasn’t been the winner for most generations. Except the 3rd and 4th, where I did like the winner best, 8th is up in the air considering whether or not Switch will be counted 8th or 9th gen and whether or not it sells more than PS4 or PS5, and obviously what each of their libraries at the end of their lives will be like.
If it’s any that didn’t win; N64. My favorite console period, with such an onslaught of classics I don’t think it needs explanation.
If the best that came in last; Dreamcast. Was ahead of it’s time and had a couple games that made me not think about getting a PS2. Some I still remember fondly as among my favorite games of all time like SoulCalibur; still the best fighting game ever made.