He should stick to BB.
And attitudes like that are exactly why he teamed up with Magic. Because people told Magic the same thing.
Magic has since been involved in Starbucks, movie theaters, property development.
Magic now owns controlling interest in a life insurance/annuity corporation, owns part of the LA Dodgers, owns part of the WNBA LA Sparks, is co-owner of the new MLS Los Angeles Football Club expansion team. And none of that is included in Magic Johnson Enterprises which has a market cap of ~$700mm.
Lebron's game show The Wall is considered fairly successful and has been licensed around the world to different markets including Canada, France, Italy and Israel.