What you mention is the downside of having so many individual options to turn on and off.
1. a lot of new players wants to play multiplayer but not accept the restrictions of someone elses server, so they just open their own one (not so expensive if you host on your own machine).
2. many just want to play with their friends or with a selected circle of people, not open their world for everybody
3. there are so many possibilities to individualize your server. Creative is not creative. Creative can be with or without blueprints, with or without flymode, can have tons of different plugins. some server-owners even create their own plugins to be unique.
In the end it doesn´t matter i think. The list is long but most people are playing Soloplay anyways. That way they can build the way and where they want. This will probably change once there are more dungeons ingame, some overhaul of crafting and building, more NPC, etc.