The trend in gaming nowadays seems to be towards ever more goal-oriented and completionist designs, but once upon a time, gameplay itself was the reward for gaming. You didn’t need to level up or accumulate resources; you played it because the playing was fun. Your reward for beating a difficult boss was another boss.
The very concept of Thrive, like Spore’s, is inherently progressive, with each stage giving you the means to rise to a bigger and more expansive one - and that’s not actually a good thing. If I wanted such a game, there are plenty of better ones out there by professional studios.
Soren Johnson says that during Spore’s development, its creators were divided over two visions for the game: one that saw it as a gameplay experience, with lots of interesting and meaningful decisions, and one that saw it as a ‘toybox’ where players could stretch the boundaries of their creativity. In the end, compromise watered down both visions, creating a mediocre experience that catered to no one.
The best way of avoiding this is by looking at why people actually wanted to play Spore. One thing I consistently saw in the community (it was practically universal, in fact) was a focus on storytelling. People loved talking about their species’ life cycles or politics in a way that the game itself didn’t show. RPs about the rise and fall of empires dominated the forums. Even the descriptions of creations were often much more interesting than playing them. I think that might be what inspired Galactic Adventures (though the single-player experience wasn’t sufficient compared to what the game was supposed to be).
If Thrive wants to fill this niche, if it wants to deliver what actually drew people to Spore, then it should become the ultimate storytelling experience. After the first two stages, the game stop being about progression; rather, all stages should be fun to play in as they are. Allow us create the ultimate parasitic species, or become heat-resistance volcano dwellers, or spread a horrifying demon-worshipping cult to the far ends of our planet, or become nomadic space gypsies, without the pressure to advance or move ever closer to Ascension.
If that’s the game you’re making, I can guarantee there is an audience.