HP has a tradition in making terrible software. I remember how they once implemented the printer „control panel“ partially as HTML files in Program Files (yes, there is a space in the URL that sometimes broke the application), partially as an ActiveX component and partially as resources loaded from an internet domain (that does not exist anymore, of course).
On another project I met an API for Oracle templating (generating PDF files from templates+parameters) that was build as a web service, but this webservice was just a wrapper around a command line application (maybe they just emulated it in later versions?) and instead of some meaningful service/method parameters, there was an array of CLI arguments on the input side of the web service (and on the output side, you should do polling to check whether the document is already generated, IIRC).
Not sure why, but big technological corporations produce, from time to time, software of a really poor quality. You would get fired in college with a term paper like that. Or if you applied for a job in an average firm with that kind of example code, they would laugh at you. But in “big tech” such software sometimes finds its way through the corporate processes.
Most often, it’s because incentives don’t exist to do a better job. And that’s not always bad.
When I worked manufacturing IT, coworkers smarter than I framed every feature in terms of “how many refrigerators will this help me sell?” Every bit of software that I built and deployed was a liability unless it helped us build and ship appliances faster, cheaper, or more reliably. So lots of things that weren’t core to the business got built up to the point that adding any more wouldn’t be worth the investment.
I would imagine the story here is very similar. HP put just enough effort into this to achieve some goal. Maybe it was all about winning a large procurement contract with unusual stipulations. Maybe it was part of a licensing struggle with Microsoft. But either way, HP probably got out of it just what they needed, and any more effort put into making FreeDOS run won’t help sell more laptops.