And yet our operating systems are still written in C(++).

Javascript web code epitomizes the "long tail" of random ideas being articulated. The code is written quickly, needs to change a lot in response to user behavior and designer inspiration. It's usually < 10k lines, so its terrible medium- and long-term maintenance characteristics are manageable. It's written by millions of independent teams to bring to life millions of small ideas used by (typically) only a few users. And that's great, we really need languages for that.

But, humor me for a minute, and let's define "the C law": Anything important enough to be used broadly will eventually be replaced by something written in C(++). Why? Because solution X not written in C is always vulnerable to replacement by solution Y written in C with the equivalent feature set, and the demand is now high enough to provide the time and talent. See: every python module ever used by more than 1M people. See: every programming language implementation (incl javascript and luajit!) ever used by more than 100k people. See every operating system, every database used by more than 1 million. See every web server running top 1000 websites. See (almost) every tech startup that becomes a fortune XXXX company, and rolls through its infrastructure rewriting its ruby or its python or its perl in C/C++/Java. See why we're not all using jitted PyPy yet (hint: those pesky c modules make real world cpython often just as fast or faster and more memory efficient).

Languages that trade performance and correctness for productivity are fantastic when the project is young, small, and of dubious value (yet), or narrowly targeted and not generally interesting. Or the browser gives you no other choice.

Consumer hardware product development just doesn't align with this kind of thinking. It races right past the C law threshold. Physical stuff introduces serious economies of scale, design costs, significant difficulty of change, etc, where shipping a few hundred of something doesn't make a lot of sense (as a business; maybe as a hobby project).

So, if you're going to (aspire to) ship a million of something, investing in the software side to keep costs down, maximize battery life, mitigate risks related to a misapplied language runtime (not designed or heavily tested on embedded), guarantee performance and latency characteristics, etc, makes sense--the compromises that are appropriate for a website because you want to make a little gamble fast don't apply... you're making a pretty big gamble, and it will take awhile to get right anyway, and your capital needs are higher in general, so doing software "right" to save on COGS is just practical.

BTW, "C" here is usually C or C++, but it can very occasionally be Java [see: zookeeper] or some other JVM thing like Scala. Regardless, it basically represents the final state reached by the tool/language/platform/project race. If your project could be replaced by a version that says "like $project, but fast/battery efficient/cheap!", you are not yet at the end game, and the C law could always be invoked (if the demand was sufficient), and your project will probably ultimately lose the lion's share of the market (or open source mindshare, or some other version of "market").

So, maybe this project is betting on our lives transforming into everyone paying more for their hardware, and everyone using a lot more small/local/boutique type stuff created by small hardware teams. This doesn't really jive with the way technology products are currently marketed, hardened, and distributed, so I'm operating on the assumption that change doesn't happen anytime soon.

It could be useful/fun for hobbyists or prototyping, though.