I think this guide glosses over the most difficult aspect: writing a package whose executables are generated reasonably reproducibly, using tools from other Debian packages. I've been a satisfied Debian user for over ten years, but I gave up on trying to package my own software. I could certainly figure out how to manually create a `.deb` with an executable and some man pages, but not how to automate the creation of…
As I mentioned in the other comment, the creation of a Debian source package has a lot of barriers, some of them good and for quality purposes, some of them bad and due to historical cruft. Documentation is also not very newbie-friendly. The actual automatic reproduction of a binary from a source package is simple - `dpkg-buildpackage`. The tradeoff you get with other distributions being quick, is less quality assura…
The crux of the problem is that all current official Debian packaging methods supported by Debian are sufficiently arcane and obtusely documented to the point that it's a high barrier to entry for people to do it right.
Personally, I've been doing RPM and Debian packaging for over a decade now, and it boggles the mind how much more complicated doing _correct_ Debian packaging is for essentially the same that happens on an RPM distribution like Fedora or openSUSE.
One of the reasons that I started using debbuild[1] for building Debian packages years ago was that I felt like I could get something that closely resembled a policy-compliant Debian package without impossible amounts of guesswork. Combined with macros adapted from Fedora and other distros[2] as an interface for Debian packaging policies, I can package things rather easily for Debian/Ubuntu using the much more straightforward guidelines from Fedora as a base.
As it turns out, it doesn't take that much effort to make packages that comply with Fedora/openSUSE Packaging Guidelines and Debian Policy with this tool, and it has drastically simplified my ability to maintain software across distributions in a way that still cleanly integrates with the distribution platform.
I wish that debbuild would be an officially supported mechanism in Debian, but it's probably unlikely without a Debian Developer advocating for it (and I suspect no one there would, as they probably like the existing system...).
[1]: https://github.com/debbuild/debbuild
[2]: https://github.com/debbuild/debbuild-macros
(Disclaimer: I am now the current developer of debbuild and debbuild-macros, though I wasn't when I first started using it)