That was my point. They homaged Gatchaman to the point where you'd only expect Gai to die only if you watched the anime.
Which... means that the lack of foreshadowing weakened it (this is why I think the epilogue's the weakest part of the show).
Gai even had a "I'm going to fire the missiles!" moment while they were in Jet Icarus. Also, Jet Icarus's Not God Phoenix flaming finishing move...
As for Gai's ending... I'm not really sure what to make of it. One way to approach it is that he wants his final moments to be with those who have become his friends, rather than in an alley or hospital.
Another take, that one of my friends brought up, is that Inoue basically wanted to set the standard sentai epilogue on its ear. Usually, the heroes return to their normal lives, better from their super heroic experience. The catch with Gai being that, as a street level guy, even though he has changed during his time as Black Condor, he's still a bit of a city thug, and gets an ending one would expect from that stock of character. Not to say I like it, but the lesson might be that the Super Hero Experience doesn't necessarily guarantee a Good End.
Anywho, I just finished Episode 21, which has another common Sentai tropes: Monsters Are People Too. Again, Inoue ramps this up by having people being excessively cruel to him, and throws in messages on pollution and corporate inventory control methods during the 90s bubble economy. Huh.
Also watched Episode 4 of Dynaman. Still goofy fun. I've been noticing 80s sentai robots tend to be able to pull out whatever before finishing with their sword. Inventions seems to be a theme in the non-action bits. Red wants to make an environment friendly motor engine, Black's an astronomer (and is also a ninja) that wants to contact aliens, and Yellow's a cowboy that wants to improve crops. His invention in this episode was some sort of noodle machine that backfired.