Once Red Hat came along, Linux basically became a commercial product, and more so as Red Hat grew in prominence/influence such that many innovations in Linux come from Red Hat development engineers (hundreds of engineers and more...). That Linux development control is solidified via the Red Hat Certification programmes, which dominates Linux instruction in the tertiary education system around the world. Other Linux teaching programs and alternative Linux certifications are insignificant in comparison to the likes of "Red Hat Certified Engineer" (RHCE) and "Red Hat Certified System Administrator" (RHCSA): https://www.redhat.com/en/services/certifications
Red Hat sponsor community Fedora builds, but in reality they manage it and provide the engineers - who work alongside the community volunteer open source developers, but really it is still Red Hat creating that. Ubuntu is another commercial product - just uses a different strategy for its promotion and place on the various Linux development steering 'committees'. Debian is small fish in terms of Linux development really - it just implements its distributions with an eye on removing 'non-free' sources from its main repos. We all follow the upstream leaders, a process which is mainly steered by commercial Red Hat (and certainly not by GNU).
Yes, a few minor distro communities (such as Devuan) try to avoid systemd. Debian doesn't, which says it all really.
In Puppy land we live in a GNU dream world of believing we inhabit the moral high ground of open source freedom. The way it is imagined here has never existed or at least it has not existed for many many decades. Puppy itself primarily relies on upstream repos nowadays. Silly thing, in my opinion, is that it relies on these upstream repos but modified its earlier package manager to first transform the upstream package formats into PPM-compatible format prior to installation rather adopting both the repos and the appropriate package-manager that could already correctly use these repos. Unfortunately that means there have been constant Puppy PPM issues with correct dependency-resolution and compatibility more generally - upstream repo package managers had already been accurately designed for handling their repos (of course).
BarryK's original Puppy's had their own repos and thus it made sense (was necessary) back then to have own package manager - but once upstream repo(s) adopted it was surely a bit silly to not use the related carefully-designed-for-repo package manager(s)? Was that a 'pride' issue - where it was accepted that upstream repos needed to be adopted but worry that adopting the related package managers might make it obvious that Puppy was no longer really an independent distro either? Note that both tinycorelinux and Slitaz continue to use their own independent package managers, but that is because they maintain their own independent matching repos. Anyway, no Linux is independent - we all follow the upstream leaders and end up having to go with the flow, to a large part, since we cannot redesign Linux at this level.
There is a certain amount of flexibility however - choice of window manager and which upstream repo and so on... You can also write some of your own system-glue-it-all-together scripts and (if unwise) adopt somewhat different filesystem hierarchies - that latter can (easily) be unwise since it can create incompatibilities (with upstream repo package organisation) and side-effects that reduce stability and often simply doesn't work... Nevertheless there are some workable filesystem hierarchy alternatives - for a particular repo package organisation (such as the way Arch does it compared to how Debian used to - Debian seems more recently to be adopting Arch's approach however).
You couldn't trust any computer OS at all if that relied on believing in one man being the auditor. Believing Linus looks (looked) after such a complex system on his own was also just a dream.