Just to make this clear, when Aikido was first named as such (not by osensei), O`sensei, had to give it a name so that it would be accpeted as a traditional Budo by the Japaneses gouvernment, this is achieved through, Dai Nippon Butokukai.
The DNBK, authorizes teaching & certification in traditional Japanese arts including Kobudo, Aikido, Iaido, Kendo, Judo, and other tradional arts from Japan.
Head of DNBK is, His Royal Highness, Sosai, Higashi Fushimi, Jigo, the chief abbot of Shorenin Temple. He is a brother to late Empress Kotaigo of Emperor Hirohito of Japan. Vice Governor, Fuku Sosai is his son, Higashi Fushimi, Jiko, he serves as the Shinmon of the Shorenin Temple.
Many of today`s exponents of Aikido within Aikikai, are also members of DNBK, including Hioaki Izumi Sensei, 6th Dan Aikikai, Dan graded also in Kendo and Iaido.
Post WW2 or not, many people still in Japan today still consider DNBK recognition, as one of the highest authority on traditional Japanese martial Arts. And many practitioners from Differetn arts Are members.
It's true that the Japanese government was using the DNBK to regulate all martial arts during the war, that's how the name "Aikido" came about.
However, that organization was dissolved, and the new one of the same name has only a slight connection to the pre-war organization and no governmental authority of any kind.
The Kendo, Judo, and Kyudo organizations after the war opposed the reestablishment of the DNBK name and today continue in their own separate organizations as well as a single group association, the Nippon Budokan, of which the Aikikai is a member (as well as the All Japan Judo, Kendo, Kyudo, Sumo, Shorinji-Kempo, Naginata, Karate and Jukendo federations).
There are two major Kobudo organizations in Japan, the Nihon Kobudo Kyokai and the Nihon Kobudo Shinkokai. Most of the traditional martial arts belong to one or both of these groups - but not to the DNBK.
As I said before, there is no connection to any major Aikido organization. For example, the Japanese page lists branch dojo in many different arts, including Aikido - but for Aikido there is only a single dojo, in Hiroshima.
Sure, there are people from different arts as members, but as far as martial arts organizations in Japan it's fairly minor today (there's nothing wrong with that). I think that if you spoke to most Aikido practitioners in Japan they would be hard-pressed to even tell you whether or not the DNBK still exists.