The question is answered in TFA:
> These “economic opportunities” are essentially a wealth transfer from new players to established ones. Gameplay requires the purchase of three Axies, which currently cost in the hundreds of US dollars each. Players who buy in treat this as an investment, since it’s a necessary buy-in in order to work in the game.
It sounds more like a Ponzi scheme in a Gold farming disguise to me.
I'm very familiar with Gold farming from Eve Online, where selling game currency (ISK) was permitted via exchange of game time cards sold by the game's developer. There was always a secondary market for game time cards sold for real money and that was legal too. The reason it all worked is because playing the game was really fun, but required to grind to get ISK. People with more money than time would prefer to buy themselves new spaceships to get blown up in than grind for them.
It really sounds though like Axie Infinity is not a fun game and no one treats it as one. So it is something new.
> it’s hard to find any reviews on Axie Infinity as a game rather than as an income stream or speculative investment