Self-described “long-term optimist” Elon Musk made another bold prediction about his car company. That isn’t necessarily good news for Tesla’s stock price. On Saturday, Musk tweeted that Tesla’s earnings could grow tenfold over the coming five years if its business execution is “outstanding.

The CEO’s politics have eroded the brand’s appeal among some buyers of electric vehicles, surveys indicate. “I used to idolize the guy,” said one Tesla driver who wants to get out of his lease.