I think your hypothesis is correct, but that doesn't make Git any less of an achievement. Certainly it is the product of technologies that existed, but it is the manner in which Git packages those features that is innovative. Indeed, much of the brilliance of Git is how _simple_ it is conceptually compared to other systems--it is the concepts that Git leaves out, not what it uses, that count.
Not sure if anyone clicked through to this, but there is a rather amusing and insightful thread between Linus and Bram Cohen (bittorrent guy) during git's development about some of the crazy ideas and innovations git has. At the time things like diffing at the object level (versus the file level) were considered insane/very hard. These are the types of advances that git made mostly on its own.
(It was two links away from the article. First the 'faster than cp -a' link then, a link on that page.)
As a side note: I'm really surprised to see Bram Cohen in the capacity of naysayer on this!
"I'd like to reiterate that _nothing_ out there supports moving lines between files, and further predict, with total confidence, that if git tries to support such functionality it will simply fail"
Moreover, git is extremely fast compared to almost every other VCS. Performance was the thing that pushed Linus to start the project in the first place, but it's still amazing just how fast it is.
Performance was the thing that pushed Linus to start the project in the first place
No, problems with the bitkeeper license was the reason git was started. Linus was very happy with bitkeeper as the VCS for Linux until some kernel contributor tried to reverse engineer parts of bitkeeper which caused the bitkeeper author to threaten to revoke the free license. Git is basically a rewrite of bitkeeper
Sorry, maybe my comment wasn't quite clear enough.
BitKeeper license problems caused him to look for another VCS. However, before he started git, he tried a bunch of other DVCS systems, including open source ones, and decided he couldn't work with them because they were simply too slow. Hence git. See http://en.wikipedia.org/wiki/Git_(software)#Early_history From the quote there it's clear that it's not a BK rewrite. git is apparently faster than BK.
Your post contains several errors and points that I feel need clarifying.
The person in question was Andrew Tridgell, the "reverse engineering" consisted of typing "help" and then observing that the "clone" command would cause BitKeeper to send the entire contents of the repository (see http://lwn.net/Articles/132938/), permitting the extraction of a complete kernel history; and BitMover did not merely threaten to revoke the free license; they actually did.
Finally, Git's data model and internal structure has basically nothing in common with BitKeeper's.
