I don't think Musk has had the biggest impact on the last 25 years. I voted Bezos, because I think Amazon has made a bigger difference in the last twenty five years. Musk's biggest impact in the last 25 years is probably PayPal, which enabled secure, convenient, online transactions, but that would have been done with or without Musk being involved. I think Gates and Jobs also had bigger impacts than Musk.
I think Tesla and SpaceEx will have more influence in the next 25 years, and indeed in the next 25 millennia. But so far, Tesla has built two cars that I can't afford, and caused Chevy to build one car I can't afford. SpaceEx has boldly gone where lots of people have gone before.
Tesla is poised to dominate the market that it has begun to catalyze. But we aren't there yet.