Partly it's demographics. The average 6th kyu I see is seldom under 35 and the majority are over 40. The only people screaming from the rooftops (and into the wind) are the very rare group of mid to senior kyu grades that are under 30. Peeps that by rights should probably be in a Muay Thai or MMA gym.
Partly it's also organisation; Aikido organisations are usually monolithic feudalistic structures that tend to be ultra conservative and are run by people that have often been running them or at least senior in the organisation since before the internet.
There's no-one really fired up to do anything; instead there's 40-50 years of entrenchment and a suspicion of anything new and a constant intake of people that aren't all that interested in or even in a position to challenge things. As we say "Do as Sensei says" "Do as your dojo does." Got a question? The answer is, "Shut up and train." Any student who doesn't find their questions answered simply leaves, the only people left are the ones that don't ask questions i.e people that aren't all that interested in doing anything other than Sensei says.
People often ask why we're not in MMA. The reason is simple; we're really good at weeding out anyone that would want to be in MMA. We have them off the mat and bitching online in double quick time. We'd rather show someone the door than show them how Aikido is relevent to them.
That said the reason we can't show how Aikido is relevent to them is because often it is irrelvent. The hierachy doesn't encourage development of Oyo waza; put your hands up if you even know what Oyo waza is because I'll put money that I've just sent a load of ni, san and yon dans onto google to find out.
How many times do we hear off Aikidoka "Aikido can't deal with a boxer" as if we as a group even bother trying? Then when someone perhaps suggests that we should be perhaps investigating ways of doing it we get blank looks. Even worse if you know how to do it you're met with complete indifference. Literally if I had gone off into the mountains and come back with a bunch of Oyo waza that could totally defeat any one in MMA the reaction amongst Aikidoka would be total indifference at best and probably outright hostility.
The fact that we could, if we could as a group be bothered, demonstrate that we are actually quite an effective art, thus drawing in new and younger people who would preserve our art and push it forward just isn't important to us.
Interesting ideas.. Although the student contingent of Shodokan Aikido may be against what you say
As a 4th Kyu, 25 year old Fan of MMA.. I feel I totally go against everything you've typed lol. but I can see why you think that, and in some cases agree. Lots of people join try it, and then disappear, but that's the same with all martial arts. Because you need to learn and can't be an all action hero after 2 weeks people get bored and leave. I can't wait until I get good at this and can start just messing around with stuff, grappling with Judoka just for kicks and stuff.
I regularly try to defend Aikido on the depths that is the Sherdog Forum (MMA forum) and usually get nowhere, I do sometimes resort to slamming the whole not competitive side a little bit, if nothing more than just to draw a line stating that Shodokan / Tomiki is different and we do have competition, at least then maybe changing some MMA fan's minds slightly. but alas I don't get a lot of support. saying that Shodokan sometimes feels like the red headed stepchild of Aikido, not appreciated by the other sections of the art and at the same time tarred with the same brush by others