I'm a firm believer in not adding needless features just to stay busy. For example, I use DEVONThink, which has not really received any significant feature updates in a few years! I've also never felt 'bad' about the long period in which there was no development on Sublime Text.
But Quiver is far from 'good enough' for me. The popup-style search is nowhere close what I want, there's no keyboard shortcut to indent list items (at least not in Markdown mode), and there are tons of ways in which the app can and needs to be improved.
I bought it mostly because of its promise, and because the storage format is really nice. Furthermore, building a cross-platform Quiver (perhaps with Electron/React Native) with some specific DEVONThink-like features is high on my list of itches I've been meaning to scratch. But until I do so, or until active development on Quiver becomes evident, I can't help but feel slightly disappointed.
All that said I'm ultimately happy to have supported a developer who put out something nice with a great data format! Just being grumbly, I guess.