It's not underestimated.
It was gaining popularity but, like with all games, it takes consistent updates without huge wait times to keep those players around.
After a year with no update and no word, people are giving up on it.
The main problem this dev has is working on so many games, people only interested in one of them have no incentive to pay him any money.
For example, i'm only interested in this game yet the dev has spent most of the year working on and talking about one of his other games. I'm not going to support a dev making games i'm not interested in on the off chance the one I do want might get an update one day.
So to put it plainly, people aren't underestimating it, they just stopped giving a shit about it.