It was inevitable that the game was going to end at some point, and five years will be a respectable total for any adult game. The vast majority don't get anywhere near as much development as that. Yeah, I'm sure it could technically carry on for another five years, if the Dev himself could motivate himself to continue. But as he's mentioned in the past, this was his first attempt at making a game, and primarily intended to hone his skills as a developer. He has other ideas that he wants to develop, which will benefit from everything he's learned creating 'Project Myriam'. But for that to happen, unfortunately this game has to end.
Having said that, there's still two years to go, which means we're still only 60% of the way through. So no reason to get too sad yet. Believe me, you're not alone in wishing this game could carry on for longer. But when you're a developer, it must be very difficult to continue motivating yourself doing the same thing for a long time, when you have all these other ideas for games, that you'd like to try to make.