He came up in Theosophy and then was influenced by a number of techniques and traditions, as they were, finally rejecting them all, though retaining a bit of a Vedantic feel in some ways, and was also very much a product of his time in others, as we all are.
I am pretty sure he didn't get exposed to any good maps (stages of insight, etc.), as those were not generally available in his day and age and they don't seem to turn up in the writings of any of the late 19th/early 20th century mystics with European influence that I know of, and, having had no exposure to them, could hardly be rejecting them.
As those who practice and teach Mahasi techniques know well, there is something very mechanical in some ways about "apply technique, results happen in the expected order", and so, having been part of a very large group over decades who has the experiment, clearly JK was wrong about some things (the basic concept that techniques could help things) and ignorant of others (techniques-based practices that lead to relatively predictable results).
There is truth in plenty of interesting things he says, and I got a reasonable amount out of reading his stuff as well as studying the history of his life, such as his having a long-running sexual relationship when claiming to be celibate, etc., which was also useful knowledge and normalizing in some ways.
One more useful set of data points, not all of which are accurate, as is par for the course in this business, and that qualifier includes my own writings, perspectives and thoughts, which are limited by my own conditioning and limited knowledge of the wide range of this stuff, which is huge.
