Is there a good source on why it ends the way it did? Is it health related? Interest? Creative trap? Break Blade predates Knight of Sidonia by 2 years. Nihei completed 2 more projects since Sidonia but I admit he's a bit strange. Vinland predates this by a few months but on much better output. Jiro is not the most productive of artist, still managed to complete Ichigeki at least with a few more side projects. Endo started and finish All-rounder Meguru, Planet of the Fools within the same time frame. Shingeki no Kyojin started after and wrapped up before Break Blade with a fuller story as well. Historie is the other fair comparison with the author going on hiatus to finish up earlier chapters. Yet Iwaaki still at least managed to finished off some side projects while working on Historie.
Of the bunch, arguably only Shingeki no Kyojin had more success than Break Blade. Still, none of the other artists had movies produced. Did the movies made the author lose interest? How much of the success and failure of the movies affected the author output/progress? It just seems incredible to me that one of the more successful seinen/war comic of the 2000s ended like this. The world and characters were fun and intriguing albeit some serious cliché.
For people who shits on this comic, let's compare this to Class Saiyasune de Urareta Ore wa, Jitsu wa Saikyou Parameter. They are both built on similar premise, protagonist is capable of controlling a huge hunk of metal in a world torn by war and politics. I am not going to completely shit on Isekai, but let's be honest, Break Blade was much better written and executed. It was not bad, until the author decided to end it like this.
P.S. forget all the weird comparison I brought up. Break Blade first chapter was released shortly after the first season of Haruhi aired, 1 year before Evangelion Rebuild 1.0 was released. Anno Hideaki wrapped up the Rebuild series with 3.0+1.0, released in 2021. The Rebuild series started after and finished before Break Blade. That's just crazy.