Pretty much this...
The main reason the server declined was due to the lack of script features, that simple. It wasn't the marketing, a 'bad' admin team, the economy, although they apply to some players and their reason for departing, the main reason was the development. Players simply got bored of the barebones script and decided to move onto other things. We're just now getting certain QOL (Quality of Life) changes and features that should have been in the script day one.
But with the recent activity from the devs, even MMartin dropping snippets, the roadmap that gives players a idea on what's being developed, shows they are trying to make a turn around for the server and getting back serious about things. The server can still return to it's prime, but they have to stay consistent with the updates and communication. When 1.8 released, there were a lot of players, former and current, browsing the forums and in game, so people are definitely still interested. While it was a great update, it just wasn't enough to bring everyone back and keep them engaged. DEVS GOTTA KEEP COOKING, BRING THE HYPE BACK!!!111