Do they?
Upthread one can read: > Activities that are not treated as software development vis-à-vis software developed by a taxpayer for use in its trade or business are as follows: […] • maintenance activities after the taxpayer places the computer software into service
Example: a one line change to ignore non Unicode codepoints in PDF files loaded in a web app (I did it yesterday.) Is that a new feature? Is that a bug fix? And if it's a bug fix, is that part of a feature that we should have developed before putting the sw into service? Is that maintenance? And what if that particular code point that triggered the issue did not even exist when we released the sw years ago (the code around it is from 2021)?
I believe that nobody has the time to dig the (tens of?) thousands of issues that a company opens and completes every year but there are a lot of gray areas to exploit if somebody has any reason to be pedantic.
The same is true for many capital assets. There are people who have time to look into these things because that’s their job.
A country wide power grid or telecommunications network are other examples that come to my mind. They are never complete, they get more features every day (new cables?), they are monitored 24/7. The owner companies also use them.