Firstly, I want to acknowledge what you share and I do understand the dilemma you are presenting. Thus, I agree for the most part. But I see something, not from a developer's view, but from a user view where things are done with little thought in getting to a desktop.
I may be missing something, but if I remember, correctly, PUP's WoofCE development for system init processing or shutdown processing has not changed. Nor have I witnessed a change by the DOGs of the forum.
The ONLY visible change I have seen from them, is the ability, like Ubuntu and other mainline distros, to merely allow discovery by SG2D for presentation to the user. To date, this is available across the board for all forum distros except 2 (which by their admission are experimental).
There has been no change to facilitate presentation for booting in ISObooter nor Ventoy accommodations. Those ISO-file presenters make no demand on the distro developer for presenting the distro nor presenting the developer's Boot Stanzas. The PCs boot bare-metal via their GRUB boot stanzas with no actual demand or request for development interaction.
That is what these ISO file presenter do...nothing more is their intent. Just to facilitate a simple method of getting the PUP listed in front of the user so one can select and boot whichever he, the user, has added to the presenter's folder.
By not needing any consideration for presenting the developer's distro, I dont see any harm or impact on the developers for getting their distro in front of anyone via a direct boot of their distro's delivered file, any more so than booting their distro expanded onto disk/disc.
Ventoy, is the newest of these distro presentation products for user selection and has gone one further than the other 2: If allows 2 features useful for users
It allows IMG file booting
it allows ISO files to be placed on system drives rather than its old requirement of keeping the ISO/IMG files ONLY on USB.
I am NOT advocating for development community change in product design. NO I am advocating for simple steps that allows new/experienced users to get a running desktop with as little effort as possible. ... AND WITH NO DEVELOPMENT CONCERNS! These presenters job is merely to present the distro for selection and afford the launch by the user. ISObooter/SG2D/Ventoy intends to do these with NO developer concern.
These 3 method and QEMU have allowed users to do such with ISO files and IMG files.
As I have said before, experienced forum users usually understand who to expand delivery contents to be placed in the filesystems prior to actual booting and use of the distro. They may not use these. Tire-kicker and those new to Puppyland would see some benefit and reduction in potential headaches, otherwise. You and all of the moderators know how to do these expansions.
Again, I am looking at ease of use via a method of selecting the distro developer's presentation without much need for any understanding other than a mere "Download and Boot" option; as the current PUP-DOG distros are currently designed. Further, these products are not limited to just PUPs, as they offer the ability for user selections of ANY bootable distro or OS these products list for user selections. Thus, I see benefit with no demand on development for any development changes or changes to any installed OS that are present on the system's drive(s).
AGAIN, I am sure this is apparent, BUT, I make no demands of developers or community to support either of these "DISTRO Presenter Products". They, I feel, exist to facilitate users to download and boot, directly and easily.