From this perspective - my intuition is that the likelihood a Kanye West led Parler will be successful is substantially greater than that a rap career will be successful. In some sense West is moving on to more plausible investments as he gets older.
West has had success as an entertainer and as a businessman - I believe he has a successful shoe company. He's famous. If he thinks he can take on Parler, that seems like a crazy challenge but one he is well equipped to take on. I would certainly believe in myself - even if I thought it was low probability I'd feel certain that it was possible.