Edit: In addition, LexManos is no longer the sole contributor, cpw has returned, and MCP has always been a separate project which has managed to keep a core team.
About 1.9, because the minecraft code is obfuscated and very complex, updating forge to new minecraft versions takes a long time for MCP to release mappings, then forge to port etc, so I'm really not surprised that updating takes a while.
Most mods these days are distributed through curse forge, which although has adverts, is reputable and curse pays per download. The minecraft forums are as buggy and crap laden as always unfortunately.
By MDK do you mean Forge? MDK doesn't seem to be used except in one forum thread.