It may be argued that Sukadeva Gosvami is not the only authority of perfect knowledge in transcendence because there are many other sages and their followers. Contemporary to Vyasadeva or even prior to him there were many other great sages, such as Gautama, Kanada, Jaimini, Kapila and Astavakra, and all of them have presented a philosophical path by themselves. Patanjali is also one of them, and all these six great rsis have their own way of thinking, exactly like the modern philosophers and mental speculators. The difference between the six philosophical paths put forward by the renowned sages above mentioned and that of Sukadeva Gosvami, as presented in the Srimad-Bhagavatam, is that all the six sages mentioned above speak the facts according to their own thinking, but Sukadeva Gosvami presents the knowledge which comes down directly from Brahmaji, who is known as atma-bhuh, or born of and educated by the Almighty Personality of Godhead.
Vedic transcendental knowledge descends directly from the Personality of Godhead. By His mercy, Brahma, the first living being in the universe, was enlightened, and from Brahmaji, Narada was enlightened, and from Narada, Vyasa was enlightened. Sukadeva Gosvami received such transcendental knowledge directly from his father, Vyasadeva. Thus the knowledge, being received from the chain of disciplic succession, is perfect. One cannot be a spiritual master in perfection unless and until one has received the same by disciplic succession. That is the secret of receiving transcendental knowledge. The six great sages mentioned above may be great thinkers, but their knowledge by mental speculation is not perfect. However perfect an empiric philosopher may be in presenting a philosophical thesis, such knowledge is never perfect because it is produced by an imperfect mind. Such great sages also have their disciplic successions, but they are not authorized because such knowledge does not come directly from the independent Supreme Personality of Godhead, Narayana. No one can be independent except Narayana; therefore no one’s knowledge can be perfect, for everyone’s knowledge is dependent on the flickering mind. Mind is material and thus knowledge presented by material speculators is never transcendental and can never become perfect. Mundane philosophers, being imperfect in themselves, disagree with other philosophers because a mundane philosopher is not a philosopher at all unless he presents his own theory. Intelligent persons like Maharaja Pariksit do not recognize such mental speculators, however great they may be, but hear from the authorities like Sukadeva Gosvami, who is non-different from the Supreme Personality of Godhead by the parampara system, as is specially stressed in the Bhagavad-gita.
Source: A.C. Bhaktivedanta Swami Prabhupada (2014 edition), “Srimad Bhagavatam”, Second Canto, Chapter 8 – Text 25