No, another reason why we don't have a huge influx of players is because the BL demo is so outdated and awful which misleads people to think BL is awful as well, which it isn't. But the demo isn't good at all. Many people know of Blockland though, which is good.
I don't think either of the two reasons you think people aren't Blockland are true. The graphics don't look bad, especially now that we have shaders. And they already updated the demo, it's not outdated. Even if it was, you didn't exactly give any reason as to why that would make people think Blockland is bad
as for the doors, JVS looks better but apparently functions five times worse than the default ones. So it's sorta like the gameplay over graphics argument. I'm not taking a side, I like them both