Well, you can get 450 KS from a single login month, which translates to either 150 or 225 SKC depending on whether the BC campaign is going. Isn't that a lot? Even after spending the bulk of your login points on things like Shanks or Skirmish stones, you can still accumulate a fair amount of seals with the remainders.

Also, when you team up with other players, you get Rem's just for participating. It's a really player-friendly system.

Finally, as I mentioned, seals are a byproduct of almost every XP grinding activity in the game. You're never getting just seals, you're also getting other things that can be converted into gil, used for character progression, or used to purchase NM triggers. I don't think it's as significant a roadblock as you make it sound.