I don't see how discussions like this signify the decline of NodeJS. Quite the opposite. Lots of people are thinking about how to do this kind of computation the right way, within the context of NodeJS. Honestly this discussion has kind of highlighted how bad almost all other platforms are and how much room for improvement there is.
So let me lay it out for you: Node's multithreading is primitive. There are in fact other languages that can simultaneously do long-running computations and serve web pages at the same time, because they are not single-threaded under the hood. That is a Node limitation, not a fundamental computing limitation. Many of those other environments can also trivially use multiple cores within the same OS process.
We are discussing the limitations of Node with regard to long running precisely because it is a limitation that Node in particular has, and that there are other environments that do not have it. We are discussing this limitation precisely because the casual presumption you make in your last sentence that Node is the epitome of programming platform, and therefore if it has a problem then everything else must suck too, is false.
I am staggered at the degree of ignorance of other platforms being displayed by the Node partisans here, because it's not "well, OK, that's nice but in practice I don't care", which I would disagree with but would at least consider debatable (and I mean that quite honestly), but rather just a continuous talking past the Node partisans entirely, with little evidence that they even understand what is being said. I say this from experience over the past couple of days, where it's pretty clear the Node partisans seem fundamentally incapable of considering the concept of "environment that does not have the fundamental limitations of Node".
Several of you seem to be expressing confusion about why some of us aren't coming around to seeing the light. To you all, I'd recommend this essay: http://www.paulgraham.com/avg.html Hint: Node is blub.
Let me be clear about my motivation in writing this, and generally trying to tamp down on the Node hype. First, it's bad for Node. I've seen this cycle before, and as fun as the ride up is, when it is predicated on false claims it tends to explode at some point and the whole thing goes down in flames. (A process that may now be starting.) Second, those of you who only know Node and think it is the epitome need to have it explained to you that there are in fact other tools that are more useful in these cases, so if you ever encounter those problems you can use the right tool for the job. Otherwise, you'll blow untold manhours trying to force a old paradigm to do something you could have done in a more modern one much faster and more effectively. I don't hate Node; I hate the hype, and the damage it is doing to a large group of people by lying to them about what the competition does.