I agree with your premises, but your solution (ceasing to operate via satellite) is not the one I would choose.
Yes, there is a lot of bad operating on AO-51 and other FM birds. Yes, a flying repeater is not the ideal way to put ham radio into space (I don't go as far back as you, but I remember AO-10 with fondness). Yes, a massive mess is predictable when DX like K5D is on the air.
Not that two wrongs make a right, but the K5D situation on HF is not all that much better. People screaming at each other on the air and on the clusters, intentional QRM, calls from fake stations pretending to be K5D, EU and USA stations arguing over where K5D should be listening, etc.
I took an HT with me on a 2008 DXpedition to Swan Island (HQ8R) and was quite pleased overall with the decorum. I was particularly happy to receive several nice emails from folks who thanked me for their first DX contact ever on ham radio.
In my view, the FM sats are an easy intro to this aspect of ham radio. Those who find it interesting and get into the sats will hopefully move up to the linear birds and create momentum for more of these. Those who don't will go away, hopefully without causing too much QRM. As with any type of beginner or introductory mode, we can't expect perfect operators (and boy, did I make a few dumb mistakes during my year as a novice).
You ask why the transponder sats go relatively unused. I think it is largely because of the expense. I've wondered for a long time why there is such a huge price differential between FM only and all-mode rigs. About the cheapest way to get on the transponder sats is to buy a pair of used FT-817s plus a rotatable antenna (I know that Patrick has worked them with an Arrow, but that it is easier said than done). You can put up a respectable HF station for a lower price. Not everyone has that kind of money to spend for a set-up that allows you to operate for only a couple of passes each day.
So I'm sorry that the poor operators on the FM birds have driven you away, but I think I'll stick it out for a bit longer. I agree with you about the need for more teaching and for easier-to read articles about sat operations, and hopefully someday you will join us again on the birds and on this BB.
73, Bill NZ5N
I'm one with fm only radio's currently. I was interested in, and got to work on doing the packet satellites. It was pretty empty, except when iss was on packet.
After doing this for awhile, my brother wanted to try the voice sats, so I turned up a few passes of ao-51 and I think ao-27. That lastest a few passes, before I decided I guess I will only do the digital sats, and probably the ssb/cw ones when I get enough gear to work them.
Now with no satellites doing anything on packet now, it's alittle depressing, I saw the japanese one doing it on the weekends now, but haven't had my station setup for it since go32/no44 went down.
Now is no44 doing these days? I see a few hits but not many.