Sometimes the barrier of entry for a show is more than just the time investment to watch the episodes week after week or back to back in a binge. Sometimes you have to push through an entire season of decent-to-mediocre (or maybe even straight up bad) TV just to get to the good stuff. It's not uncommon for a show to spend a season finding its footing and its voice before really getting off to the proverbial races. It's just unfortunate that these specific shows got so good only after we struggled through a particularly rough start.
Fans are lucky none of these great shows were canceled because of the first season, but when they enthusiastically tell someone they just have to watch this show, they do so knowing that their friends, family, and fellow TV-watchers might simply give up before getting to the first episode of the second season.