Quoting Russ Allbery <rra@debian.org>:
Another problem that would have to be resolved is security support over the >lifetime of a Debian stable release. I can seecreating a new Debian package if some Debian developer wants to put in the work to better integrate the software into Debian, but just dropping the vendor's Debian package in our archive seems like entirely pointless makework that potentially causes problems for the security team down the road. --
Please elaborate.
For closed-source, non-free large commercial software packages like Opera (and Oracle Express, and others) that are already distributed as Debian packages by the companies that sell them, it's unclear to me what advantages there are in including packages in Debian non-free.
Making the software available to custom debian projects in the debian repository seems like an advantage.
"Everything should be made as simple as possible, but not simpler." Albert Einstein