Hi there scuzzb494,
I must say I disagree with you concerning PD houses and the need for demo groups to have a "publisher".
As a former mega-swapper in the 90's with over 150 contacts internationally, I can safely say that groups had no problems getting their stuff out to people inside or outside The Scene. We swappers lived for spreading demos, intros, disk mags and so forth - it was a lifestyle.
I mailtraded floppy-disks with hot/new stuff with people from Australia, Poland, Italy, Spain, UK and so forth. I used to receive apx. 5 parcels with stuff per day. If I got a new demo, I'd send it out through the network and those I shipped it to spread it further to hundreds of others. It was a great system and very fun. Got a lot of friends all over the world because of this. 
The stuff then got spread to people not swapping themselves, like friends, neighbours, at school and so forth. The reach was in the thousands and thousands. A very good demo could be found in most users disk-boxes.
You also had BBS's that hosted demos. One job on The Scene was to be a modem-trader. These guys uploaded new demos to BBS's all around the world. They then got downloaded and spread yet again.
PD-houses could haved served as an entry point for some to get a new demo, but I can safely say that this stuff did not need PD-houses to be spread. 
We also had copy-/demoparties were people met and exchanged stuff.
Britelite is very famous on The Scene btw and has been active for years. He knows this stuff in-depth.
I also, if I remember correctly, recall Kefrens - famous Danish group - having a fight with a PD House for charging money for one of their demos.. am I correct here?
And.. The Scene is still going strong. There has been many Amiga releases the last year, a lot of nice stuff. And groups you are talking about from back in the days, some of them are still alive and kicking! 
I'm still in a couple of groups, but not very active these days.
Have a look here at Pouet.net for Amiga releases 2016 and 2015: http://www.pouet.net/prodlist.php
As a humble user of the Amiga from the getgo I have enjoyed collecting disks for a very long time. I was very remote from the user groups and such and to be honest enjoyed my very solitary interest right up until the 2000's. I bought regular magazines and obtained my software from shops and the like. However, as the Amiga scene started to dry up the only source of software and the like was through the PD houses. So looking at it from an Active Amiga user the demo's that I received were either from the 'published' lists in magazines or actually from cover disks. In truth most were from my own creations.
The point about published lists is very very important to me because as I collate and build my collections I need some reference point. A disk that simply says ' blank ' or uninitialised is of no use. The fact that a PDHouse would label many disks and order them by number is very useful. I get numerous requests for ... ' er that disk with the rotating spheres like a snake on it and scrolling words that say ... blah blah ' music by Joy Division. So what do I do. The disks are a nightmare.. So I copy and label them. I read and review them. Most are utterly junk, but there are the odd gems.
I say all that because I wasn't part of any swapping group and I guess I reflect a core element of the Amiga users that literally didn't even get involved. However to make this process work and to be understood and to collate now you are hard put to find a recognised source of listed data. The only people that 'published' anything in a recognised format appear to be the PDHouses, god bless them.
Scuse my ignorance of the subject. However, MegaDemo II from 'X' abusing fellow users with disgusting language, 'today' on a disk that only self boots from my A500 and stalls unless I click the mouse and let it run again is tricky to identify, catagorise and store for future use. The saving grace for me is the 'published' list and the label and the a number and maybe a description. The message may be on the disk but its a pig trying to get there. In truth its relevant to the period and was not structured to give any order. Dunno.
By the way I do hold the view that demo creators 'needed' a publisher. What went on in the background may well be the reason the vast majority of works are going to get lost. At the base was probably the same thing that was rooted into scanmastery, and that is the legal issue of the product. Dunno.
Thanks for the comments. Shows that Amiga users did occupy different worlds. As for today, I am not really interested. I only dwell in the past. I will continue as I am doing today wading through endless dms files with no label trying to organise and label stuff so I can find it again. Now playing ' The Mighty THR Deadly Persuits 36. F5 Contex Divine Intervention ' Hope you did OK in your exams... so funny. Great bit of music.
Just wish 17 bit hadn't deleted all the disks that had copyright issues or I may just have had a more healthy stock. Also... disks don't last and a lot are falling over. Ar hum.
