TD,
Further reading in legal filings shows that what you suggest is, more or less, how Watchtower presents its activities. That is to say, the Watchtower organization asserts it has an ecclesiastical hierarchy but between congregations and Watchtower Inc. there is no legal chain-of-command; hence no legal hierarchy.
As you can imagine lawyers have hashed this subject out, and most notably in the Charissa et al v. Watchtower case in California and the earlier Brogdon v. Ruddell (aka Bonham vs. Watchtower) case filed in Texas.
Opposing counsel has argued the Watchtower system is a de facto legal hierarchy if not by statute or common-law.
Undoubtedly, whether successful in its attempt or not, Watchtower has obviously (not a word I use often) made every attempt to structure its organization as both hierarchical (ecclesiastically) and congregational (legally), and it has done so in order to enjoy all the legal benefits of both forms of control with as little of the disadvantages of either.
Marvin Shilmer
PS: One potential contradiction in this has to do with the Brogdon v. Ruddell (aka Bonham vs. Watchtower) case. Regarding property rights Watchtower asserted that a congregation is subject to the direction of Watchtower. On the surface at least, this supports opposing counsels’ view that Watchtower has crossed a legal threshold from congregational to ecclesiastical.