This is for Mark really, but I think it may be interesting to see what others think.
I started wargaming in 20mm. I think that is true for most of us who grew up in the 70s and early 80s in the UK. It is almost impossible to explain just how limited your options were as a wargamer in those days. Initially it was just one word. Airfix
I know there were other manufacturers out there making metal models, but if you were like me a young lad the chance of ever discovering them was slim, and even if you were aware you still needed to write and send a self addressed envelope (and possibly a postal order) to get a typed and un-illustrated catalogue. Luckily we had Airfix, and it was available in just about every newsagent and toy shop in the country.
Airfix were the main supporter of my wargaming from the start. That meant for most "periods" their soft plastic 20mm (1:76) figures or polystyrene kits, supported by their rule books initially loaned from the library and illicitly photocopied.
WW2 was the big interest for me. After all the war ended only 30 years before and we all had family members who had taken part. It was possible to play other periods of course, and the idea of fighting Agincourt using just the figures available in the two "Robin Hood" boxes must have occurred, but the main arena was WW2. Choice was, well, limited. Airfix had a vast breadth of range, but it did lack depth. Germans could happily fill their order of battle with Panzer IVs, Panthers and Tigers, and the ubiquitous German Recce set provided a Kubel and 222, but that was about it. Similarly the Brits could get their hands on a Churchill, Sherman, Crusader and Matilda. This made for exciting times if you were so inclined, trying to convert a passable Cromwell out of plasticard and the wheels from a Crusader etc. Later, Matchbox joined the fray, adding such much needed kits as a Panzer II and III, and a Sherman Firefly. All of this was in what we now call 20mm, and as a WW2 wargamer there was nothing to compete.
But today 20mm is rapidly shrinking into the shadows. Initially 15mm, then more recently 28mm have dominated WW2 gaming. 20mm still survives, but it is no longer the first choice for me and many others, so why is that?
Firstly I should say in many ways it IS the logical scale of choice for some games. Availability of cheap plastic kits in an amazing variety, some, such as those by Dragon are available painted to a standard most of us could only dream of. Figures have also come a long way, and figures by companies such as AB are frankly streets ahead of most of their 28mm rivals in terms of detail and animation. Range is also very comprehensive. In 28mm I only know of one manufacturer makes Belgian infantry, not so in 20mm. Try finding a Sdkfz 132 Marder II in 28mm, no problem in 20mm. Price is also VERY alluring - 20mm kits being equivalently priced to 15mm ones, and usually a fraction of a 28mm one.
The problem is the tyranny of the masses. 15mm has blossomed with popular rules like Flames of War rapidly dominating the market at the "Company" level of gaming. 28mm has followed suit at "Platoon" level even if Bolt Action has a very suspect concept of what a Platoon actually was. What that means is that if you want to play a WW2 game, those scales are where you will have the best chance of finding an opponent. And that, sadly, is a fairly huge factor. OK if your club or group want to either stick with 20mm or start afresh, but once you are in, you are committing to a very fixed group, and if, as often happens, you fall out or move on, then you may end up trying to play solo.
I would also add I like 28mm as a scale to paint. As I grow older I can no longer conceive of painting some of the smaller scales to a standard I would be happy with. That may not include 20mm yet, but it is getting there. And then there is the spectacle. a Tiger in 28mm is quite a lump of eye candy in a way 20mm cant quite manage.
And of course, once you commit to 28mm, it makes little sense to play other scales for similar projects. I'm excited at the soon to be released Chain of Command Fall of France expansion. If I were starting from scratch I may conciser 20mm, (edit - I originally typed 28mm instead of 20mm) but I'm not. I already have quite a bit of 28mm kit that will port over, and a group who prefer to play in 28mm (and another local group who would look puzzled at the thought of playing in 20mm).
So that is why, with some sadness, I wont be starting 20mm again. Sorry Mark, it just does not make sense to me, but I understand why you make the suggestion.
Comments please - let's try and discuss