Hi @cherute, thanks for your reply, valid question. I might write a post about what we know, and what could happen.
The Splinterlands team mentioned multiple times on AMAs that land is for everyone, even for those who don't own any.

1. The core of the land expansion impacts the fighting system with the introduction of Items and Spells. This will bring a new phase into the game, where you can see the battleground and select Items and Spells, which will impact the outcome of the game. Items and Spells can be crafter only in the Land expansion, the Splinterlands team won't sell items and spells in pack or in their store.
   I went a bit deeper into how items and spells might work in my previous posts:
   What do we Know about Items and Spells and
   How Could It Work - Items and Spells A Few Thoughts About The Expansion

2. PvE on Lands - Nate Aguila mentioned in recent AMAs, that they would like each player to be able to have adventures across the lands, most probably in PvE fights. This was not specified yet. But as Shards/Essences are needed to craft items, which can only be earned by fighting it is very likely that sooner or later this PvE aspect of the game will come. It might happen that these will be added after land is released in a later patch of land. It could also be, that shards can be earned in ranked battles or tournaments.
   Here I would add also, that as every player can earn shards/essences needed for crafting and these are tradeable items. So every player can have an additional income by trading these shards.
   There are a lot of opportunities (though this is only a speculation) for minigames on land. I might get into that in a post.

3. Renting of buildings and plots - As all land can be rented out, each player has an option to try out, what it is like to own a land. Just like currently anyone can play a Byzantine Kitty through the renting system.

I hope I could at least partially answer your post.
If you think Land still excludes player base, then can you please elaborate why?

PS: Take a slice of !PIZZA for the great, though provoking reply :)