I think you may be exaggerating Aristotle's importance in his lifetime.
He's famous now, because he is one of the few ancient intellectuals we know about, but back in his day he was simply a more famous philosopher, just like Einstein among modern day scientists (he is only one of many, and arguably not even the greatest).
I'm sure there were plenty of nobles who looked down their noses at Aristotle, and probably quite a few priests who would have reacted quite poorly to anyone implying that he's more important than them. He was probably "friends" with the leaders of his time in the same way that Michelle Obama is "friends" with Oprah: it's good publicity for both of them.
However, this is not to say that you couldn't have a "philosopher" (or scientist) gain great recognition, and a political position in today's society.
This person would have to:
- Be very intelligent
- be very charming (being rich wouldn't hurt either)
- Be perceived to have contributed greatly to the world, perhaps even be regarded as a hero of sorts
- Be quite outspoken, and comfortable with being in the spotlight, as well as promoting their ideas and work.
Einstein fits many of these criteria. Justin Beiber does not, because while he entertains the masses, he is not seen as having contributed much to society. So back to Einstein, he was quite famous, quoted in newspapers, sen as having had a great contribution to America winning the war, and was thus respected by the general public. At the same time, although clearly a big of a loner, he was also present at certain famous parties, and rubbed shoulders with Hollywood stars and politicians (probably not willingly).
There are a couple of scientists and famous people who fit that bill today: Bill Nye, and Neil deGrasse Tyson are both popular, intelligent, outspoken, men, who have no problem expressing political opinions, and trying to guide people down the path of scientific enlightenment.
Bill Gates is a very smart guy who revolutionized personal computing, founded one of the biggest companies in the world, and is generously investing his money and time in trying to solve some of the world's problems through his many charities and donations.
Stephen Hawking is also a widely recognized scientist, who will likely go down in history, just as Einstein has. He too uses his celebrity status to support certain ideas and ventures, such as the Mars missions.
Take someone like that, add a bit more political savvy, a little more charm to woo the masses, and I think you'd get a sort of intellectual Kim Kardashian (I can't believe I just said that).
Such a person might be able to leverage their knowledge and fame (possibly also fortune) into getting some sort of prestigious government position.