Reading Peter Haskel's Sword of Zen, on Takuan and his life and writings.
I was struck by this passage regarding Takuan's refusal to appoint a successor or give inka due to his view of the degradation of the Zen of the time and the unsuitability of students:
"The problem is, as Takuan suggests elsewhere, is that the integrity of Dharma transmission in the temples has been compromised. Students lack the self-motivation ad independence necessary in the quest for enlightenment, while teachers shamelessly cosset and promote their favorites. Takuan contrasts this to his own youth in the temples, when a Zen monk would spend years without a designated master, practicing alone and traveling on pilgrimage from one teacher and temple to the next till at least he was able to attain realization by dint of his own strenuous efforts. Only then did he receive acknowledgement from a qualified master, who by testifying to the student's experience became his teacher. Nowadays, Takuan laments, Zen monks no longer travel on pilgrimage or leave their home temples, in effect having become laymen with their heads shaved. Their teachers dote on them, arbitrarily declare their studies complete, and write out certificates of inka, making Dharma transmission a kind of charade and an increasingly incestuous transaction."
Further, Takuan goes on to note that all of Daitokuji's great teachers had come from other temples, and that they and even he would be excluded from the temple's ranks under the then current "parochial system."
(pp. 105-106)
Granted we are talking a long time ago, but seems to be some parallels with the transmission of martial traditions as well, starting back around the same time. Takuan was born 1573, and his youth would have been right at the dawn of the Edo period, which is when it seems things went south (thought later the book discusses how Ikkyu thought much the same thing some time earlier).
Thoughts vis-a-vis koryu? I think its telling that when you look at how many ryu, ryuha, splinters, and new ryu sprang up back in the same days - when exponents studied with, usually, several teachers then started their own schools or branch schools - something similar was going on.