All who play the browser game shovelware on Nutaku know that games could be terminated at any time for any reason, regardless of how much money and time you've sunk into them. That's why you stick to popular games that are less likely to get an early axe. Given the neglect that Aigis suffered throughout its lifespan on Nutaku, it should be no surprise that it met an early end (despite its popularity).
As for KamiPro, you bet I'd be angry if they closed this game down while I was still active. Whether I'd migrate to DMM is an open question, since I know Japanese and could use the same tools I used to read Himegari. I'm not really keen to pay-to-play JP browser games though, especially if the English community disintegrated or was non-existent.