There are many examples of upstream developers who maintain the Debian packages of their work
within Debian. What it does require, though, is that they take the time and effort to become
familiar with Debian's policies and procedures, and thus become a part of the Debian
development community.
Being upstream does not confer you any formal rights beyond what you would have otherwise, but
it does lend you some social capital that you can spend to getting the packages under your own
maintainment - assuming you are willing to consider Debian developers your peers and act
accordingly.
As a Debian developer of nearly ten years, I find it shameful that some Debian maintainers do
not cultivate good working relationship with their upstreams. However, there isn't much I can
do about it, considering that I don't have the time or energy to devote to pushing this
matter.