Yeah, it does seem like the steam sort of ran out for most people.
And Falconius is right. It wasn't originally to be a long term thing, but people seemed really interested so we went with it.
Some will return and do more development... but I sort of think most won't.
Most were joining to be part of the 10 year thing.

The land sizes are just a sort of accidental side effect of us/me not really planning it out well enough.
You estimations could be entirely reasonable. Since we didn't plan, there's no real statement of what level of development and age for this world.
If it were early civilization, populations might be much lower. Later civilization and populations could be quite high.
It would also depend on wars, disease, natural disasters and other mass death events as well playing into populations levels.

I anyone has any ideas for things that might get people more interested in another wave of activity, let me know.
I have less time now than when I started this, but I can still try to help push another movement of activity.... maybe.