Masha'Allaah that is a good question and many good replies have been given.
As mentioned above, it may be that Allaah (swt) knows it is better to delay reaching that goal until we are ready, hence it is His way of preparing us for it. Perhaps the things we learn along the way will allow us to derive much more benefit when we finally reach that goal Insha'Allaah. And one of the greatest things to prepare is the right intention for that goal.
It is also a great test of patience. Barriers don't necessarily have to be broken, but I guess it depends on the circumstances. But things might go better if you can find a way of achieving your goal without causing damage elsewhere. It's no good rushing into something and then finding you have created more problems than have been solved.
I think one of the most beautiful things to remember is have the intention
. Intention is a very powerful tool. A person can be rewarded for something he didn't do, simply because he intended to do it if it were in his ability to do so. So even if you're held back from your goals but in your heart there is a firm determination for a noble goal like seeking knowledge, you could still be rewarded for it. Allaah knows best, but maybe this is similar to the following:
Jabir (May Allah be pleased with him) reported: We accompanied the Prophet (PBUH) in an expedition when he (PBUH) said, "Some people have remained behind us in Al-Madinah, and we never cross a valley but they are with us. They share the reward with us because they have been held back by valid excuse.''
In another narration the wordings are: "...by any genuine excuse.''
In another narration the wordings are: "They are your partners in reward.''
Commentary: This Hadith has already been mentioned, and we learn from it that a person who does not have the energy to take part in Jihad, his sincere intention to spend his wealth in the way of Allah and to lay down his life for His sake is enough for him, because by virtue of his intention, he will share the reward of Jihad with the Mujahidun.
Ibn Abi Hatim recorded that Al-Hasan said that the Messenger of Allah said, 'Some people have remained behind you in Al-Madinah; and you never spent anything, crossed a valley, or afflicted hardship on an enemy, but they were sharing the reward with you.' He then recited the Ayah,
[وَلاَ عَلَى الَّذِينَ إِذَا مَآ أَتَوْكَ لِتَحْمِلَهُمْ قُلْتَ لاَ أَجِدُ مَآ أَحْمِلُكُمْ عَلَيْهِ]
Nor (is there blame) on those who came to you to be provided with mounts, when you said: "I can find no mounts for you.'' [At-Taubah: 92]
And Allaah (swt) knows best.