It seems to me like your dislike of bots has got you tunnel-visioned into this concept of "the earning opportunities must be proportional to the amount of in-game assets acquired and held", and you're ignoring or de-prioritizing the core values of this game. What are you ultimately trying to do? At this stage of the game's lifetime, you're trying to grow and reach new people. The game should incentivize new players to join and stay. Opening cards from reward boxes has been proven time and time again, by so many games, to be successful at keeping players engaged and motivated to keep playing. Your average NEW player isn't going to check out the market with their handful of credits because they won't know what to buy. And they will look at the outrageous prices of some cards, and look at the credits they accumulated so far, and be demoralized and quit.

You compare this game to Magic: The Gathering but to put it bluntly, Splinterlands is not as fun. I'm not saying it won't ever be as fun, but right now it is not as fun for most people. People have less of an incentive to buy cards because there is no concept of a "deck" in this game, so people won't go out and buy specific cards to complete their deck, or to build a new deck around. And honestly, the concept of owning digital assets is still new and hard for your average new player to wrap their head around. Your average new player is much less likely to fall in love with the game or with specific cards, which would drive them to be more invested and to start collecting. People will not play the game just because it is free. It's just too early in this game's lifetime to be making a change like this.