Arguably, software fits this definition, and under 1221(a)(3)(C) it would not be a capital asset for most closely-held companies (eg a lot of bootstrapped firms).
Revenue Ruling 55-706 provides that IP created by employees of a corporation does not fall within the scope of 1221(a)(3).
And generally, corporate-created IP is treated as a capital asset on the books. This is in line with how capital assets are generally treated; as other commenters have noted, the expense of building a factory (including the salaries of the construction workers, if employed directly by the taxpayer) is also subject to capitalization.
Considering that this entire discussion revolves around how the law is misaligned from the economic impacts of business activities, it is a circular argument to use law to explain and justify your argument.
Considering that this entire discussion revolves around what is and isn't a "capital asset," which itself is a legal term, I would suggest to you that the law is all we have to argue about it. And the law, in general, sucks here.
For most companies, 1221 doesn't apply, but some companies are going to get screwed on this front by having to incur a capital loss to pay for something that is not a capital asset.
In a less legalistic sense, I'm not sure if there are many companies who provide software-backed debt anyway. That would make software less of a "capital asset" than almost any other intangible asset out there.
Arguably, software fits this definition, and under 1221(a)(3)(C) it would not be a capital asset for most closely-held companies (eg a lot of bootstrapped firms).