I always got the feeling with Ideon and Dunbine were viewed by the anime-viewing public as 'the things Tomino is doing before he gets back to Gundam'.
No, these shows were both really big hits in their own right if you go back and look at anime magazines published at the time. Ideon had its own fan convention at one point, if I recall correctly. Dunbine spawned tons of merchandise that lasted throughout the 80s.
The reason why Gundam got franchise treatment and Tomino's other stuff didn't was largely driven by the success of Bandai's Gundam model kits. Bandai had difficulty selling kits based on other IP and eventually wheedled a sequel out of Tomino and Sunrise after the compilation movies and reruns did well.
Once Bandai got the first sequel, they got more, and then they just up and bought Sunrise... and the rest is history, pretty much. I personally don't think it's coincidental that the explosion of creativity in 80s mecha shows begins to rapidly dry up after Zeta Gundam comes out.
The genre is a shell of itself by 1988 and you don't see signs of the next big mecha boom-- which was very very kid-oriented-- until 1990. Evangelion arguably picks the genre's development back up where L-Gaim and Five Star Stories left it, but Evangelion is arguably a lot of things.
Eva, on the other hand, was viewed as 'THIS IS THE NEXT BIG THING'. Presentation is 8/10ths of selling a property.
This is not true. Evangelion wasn't promoted heavily prior to release in Japan and wasn't expected to be such a huge hit. This lead directly to GAINAX's big accounting scandal in 1999, the company at the time just wasn't equipped to deal with all the money Evangelion was making.
Evangelion happened because TV Tokyo commissioned a mecha show from GAINAX that was expected to be in the vein of other shows popular at the time, like Macross 7 and Iron Leaguer. GAINAX was a niche studio at the time and most of Evangelion's early popularity was driven by pure word-of-mouth buzz.
Now, the US release of Evangelion was hyped to the moon, but based largely on its already-staggering and unexpected Japanese success. Evangelion bore no resemblance to anything other anime airing in Japan
at the time. It was much like Twin Peaks in the US, people tuned in just to try and figure out what the hell was going on.
