HistoryPorn

You don't spend millions on data analysts who gather voter data from social media, government data advertisers and other sources, you don't have photographers, videographers for every public appearance of yours, you don't have psychologists and communication specialists who decide what you'll say, do and express with your face. In general, you don't plan ahead every move you make when people will see you and you don't control your entire environment, the people you will interact with and what you will see and do every time.

You seem to have a really simplistic/naive view of how politics work at this level with the analogy of an ordinary person you gave. You need to realize that these people have absolutely nothing to do with you or me. These people will never tell you who they are funded by, who are lobbying them, who they owe to, who influences them, who threatens them and why they take most decisions, they will lie, they will hide their wealth, they will hide their ties. The only reason they are able to compete for presidency is the fact that the rich people support them, because their media take their side(channels, newspapers, websites) and their money fund their campaigns. So they will always, necessarily serve their interests, that's the deal, otherwise they will drop them and go to the next willing politician. This means that the big politicians can never tell the truth.

So with all that said, the fakeness of their campaign reflects the irreconcilable situation they are in, having to serve the 0.1% and having the people as a means to this end.