There should be no surprise in the Mariners low rating. They haven’t had a good farm system in 5 years, and some bad trades, an unwillingness to sell vets, along with mediocre drafts have run the system dry.
There are a few bright spots, namely Kyle Lewis and Evan White, who rank as the top 2 Mariners prospects. However, the Seattle Mariners are not in the same dire straights as most teams would be with the worst farm system in baseball.
It sounds odd to be sure, but the Mariners are actually in a good place now, and should be alright in the future.