If the game was called "Minetest Modding Base", "Minetest Core" or whatever, and people were warned it's just a base, it'd be fine. But it's not: Minetest Game is the greatest factor pushing new players away, as it's shipped by default with Minetest, having people thinking it's Minetest itself.
Every time I have someone downloading Minetest - Every. Freaking. Time. - I have to warn them to NOT play in singleplayer, at least not without having downloaded something from ContentDB first. This because, what people expect from a game/engine which resembles MineCRAFT starting by its very name, is to play a MineCRAFT clone by default. So wait: no monsters. No nether. No villagers. No blocks dropped. No challenge. NO GOALS. Hence the uninstalling and the very bad first impression. As I stated multiple times, this is very very very bad advertising. I don't have data, but if I had to guess how many people uninstalled MT after the first experience into a MTG world, it'd be A LOT.
Also, I understand MT actually was born as a game, but that idea evidently failed, because this is NOT a game, this is THE FOUNDATION to create a very specific game (Minecraft, which afaik it was the initial goal). This is "create your personal Minecraft without sweating too much... kinda". So, if some developers keep denying that Minetest and Minecraft are the same (paramat actually called it Minecraft-like), this should be at least not be shipped by default. Because the more it gets shipped by default, the more likely modders will create mods depending on it, rooting it into the status quo even more, creating more bad advertising and pushing away more potential players.
And in all honesty, we don't need another Minecraft: pragmatically speaking, people nowadays are not taught the difference between proprietary and free software in school, and definitely it's not a hot topic in general.
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Our society is all about productivity and efficiency, there is no time to think about what's ethically right or wrong (and let's be clear, this is bad). People use Blender because today Blender is professional enough, not because it's free software. People rely on Wikipedia because "it's there and it helps", not because it's about free knowledge run by a non-profit (in fact they do the same with Google Books).
All this to say most people won't do the effort to play Minetest instead of Minecraft just because it's free, especially when it's not as efficient/fun as the original. So sod it, let's create something which is not constrained by what Minecraft is in the first place WHILE explaining people the importance of free software! And in order to do so, MTG must go.