That seems less about "steampunk" and more about how magic essentially replicates early 20th century and 19th century technological developments.
The problem is that magic isn't replicating 19th and early 20th century technology in the Eberron setting. It's creating armies of mechanical men, rivety giant robots, and flying ships that look and feel like seagoing vessels. Combine that with the specific 19th century technologies that magic replicates as part of the setting (telegraphy, locomotives, and continual flame gaslights), and the setting starts to feel like a fantastical 19th century, which is why a lot of people read the setting as steampunk.
If you don't see it, that's fine. We can agree to disagree.
In the introduction of the Eberron Campaign Setting, it provides ten points about the setting for newcomers. One of which is that it's a world of intrigue, sabotage, spies and espionage, corruption, crime boss, competing trade families, archaeological-focused universities, etc.
Those elements aren't necessarily associated with noir. I mean, putting aside "archaeological-focused universities" and "competing trade families," which aren't associated with noir at all, the elements you've listed are just elements of spy fiction and crime fiction. James Bond films contain many of those elements, but nobody would confuse them with noir. Meanwhile,
Sunset Boulevard contains none of those elements, but nobody would mistake it for anything else.
Noir is notoriously difficult to define, and I am not going to attempt that here, but it's less about subject matter, and more a matter of tone, themes, and (of course) visual style. While it's possible that other materials hit closer to the mark, the Eberron materials I've seen don't even seem to make an attempt at noir.