Yes and No.

Yes because there are such game exist , you earn their in-game token which can be trade and sold in some big exchange
Example SLP (Smooth Love Potion) & AXS (Axie Infinity) is the token use in a Game "Axie Infinity" can be trade in Binance (Exchange) ,When you think of start of game , go and read their whitepaper or any technical document published , they will mention how they maintain their in-game economy and keep the game alive for years , most importantly is their road map and their next steps , what have being achieve so far.
To start such games , most required to have some initial investment ,then only you are able to earn their in-game token.
Recently there are some games which emphasize "Free to play & Play to earn" , this type of game is similar to the above but with 0 cost to start , means they will give you some basic stuff to start (Free to play) , then u can buy some thing more powerful (Investment) as u go along the way. This type of game are mostly more games oriented and less investment oriented.



No because their will be 100% some bad eggs around , they will create some easy and silly games to lure ppl to invest into their investment pool (Reading their whitepaper is very important) , once they think the pool is big enough , they will take everything and run away, this case there are many example around ,just google it.