I can't speak to the claims about potential profitability of GameStop's business ventures, but one theory endorsed by a lot of the /r/wallstreetbets and /r/SuperStonk redditors is that hedge funds still have significant undisclosed shorts and we have yet to see the "mother of all short squeezes" (MoASS), in which case the stock price can be well in excess of what is justified by future profitability.

Related to this theory, a lot of them believe the ease of closing short positions is facilitated by shady phantom shares and are trying to stamp that out by directly registering shares with the broker Computershare.

Disclaimer: I own GME stock.