"starters are born, not made"
I have to disagree with this. I know that if you consider only evidence from the pro's, it would seem to be true--guys never really seem to improve, or even change, their start, with very few exceptions.
But I know that it can be done, because I have done it myself. I have 5 entirely different starts (jump start (Johnson), sneak start (Fraser-Pryce), long start (Thompson), stutter start (Collins), and pivot start (Powell)) from among which I can choose. It IS possible to learn a new start. Also, it IS possible to improve a particular start and improve the first 10m, especially of course soon after you have learned the new start.
The different starts are better- or worse-tailored for a particular athlete--everybody finds one that they are reasonably good at, that they can execute when the time comes, and that hopefully is reasonably forgiving on the particular athlete's body, as they all involve different joint angles and force production and development.
The thing with the pro's is that they all have pretty great starts, even the ones that don't look so good. Look at Lemaitre--his starts look like crap, but he still runs a 6.5x 60m, which you don't do unless you have a good start.
The point is, though, that these guys we are watching are all striving to be the BEST of the BEST, and it is therefore fair to compare their starts with each other.
I agree with you about Blake's running, it looks technically good. I might even agree with you about his start--really, it is pretty good, and is a kind of sneak start that in my experience is rather forgiving on the body, in particular on the achilles (in contrast to Powell's pivot start, which I find very hard on the achilles). But then again, Thompson's long start is also very easy on the achilles IMHO, and can be executed faster by Thompson over the first 10m than the sneak start can be executed by Blake over the first 10m; however, it may have other bugs for Blake, and just not be "natural", so that he couldn't produce a reasonable start without having to think about it.
In the end, I would agree with you that if the other .10 doesn't come from his start, it is unlikely to come from his running.
But, Powell is the big duck, he even ducked Blake in London this year. The "injury" stuff was b.s.. Ultimately the top guys are all ducks, as they all have something to lose by losing, especially by losing more than once. The way it is set up is interesting--we can take different times from different venues, different fields, different conditions, etc. and try to compare them, without arriving at a definitive answer to who would win a head-to-head matchup--hence, tension and argument builds until the WC's or Olympics, which we just MUST watch, since we've invested in the program.