We all hit a plateau at one point or another. Take the time to forget about the big picture every once and a while and focus and take pride on the little achievements you make along the way. Don't think, It took me a year to get kongs oustide, I must have a problem with my training. Instead, focus on the fact that you are now able to do them outside! Make small goals, such as: This week, I want to be able to kong an obstacle that is half a foot longer than I can kong right now.
Even if you didn't achieve it, at least you made progression, and at least you put your heart into it and made a good, honest effort, and come back to it some other time or just keep working on them. Everyone handles different movements differently, and you won't always get it right on the first try. Realize where you want to be, and then forget it for the time being. I use it as a reference point, such as: When I'm incredibly awesome at parkour/freerunning, I want to kong gainer. So then I choose a time when I feel is right, and start making progressions up to that goal.
In short, no, don't quit.