The code bloat of
what exactly?
Are we talking about the kernel or the entire distro?
Let's look at one of the favorite whipping boys from uninformed folks claiming linux systems are now bloated: systemd.
In many ways the consolidation of various disparate userspace components that occurred with the advent of systemd has substantially simplified the task of contributing to anything it covers.
There's now a mono repo encompassing a huge swath of the core of userspace with far less code duplication than we used to have in the bad old days where every little component was a snowflake project managed by its own respective cabal with its own mailing lists (if you're lucky) and its own ideas of how configuration files should be parsed, services installed/enabled/run, and generally a huge snowflake pile of redundant functionality.
Anyone with basic C knowledge now can clone the well organized repo and in very little time be reading and modifying code in a DVCS, and with systems and processes like git and github in place you can have your first patch up in the form of a reviewable and upstream-mergable PR in under an hour, without anyone else's involvement!
If you don't think this is has all lowered the barrier substantially for individual contributors interested in understanding, modifying, and contributing changes to the code underpinning their systems, you simply have no idea what it used to be like.