Many people who have become

[Bassim]

I'm not sure if my sentences sound natural. Would you please correct my mistakes? This is just an exercise I wrote spontaneously.

Many people who have become politicians often say they went into politics to make a difference. But in the end, the only palpable difference they make can be seen in their bank accounts, which has become substantial. Some of them come as outsiders with humble backgrounds and ordinary jobs, but as soon as they have became part of power, their mentality changes, even if they would never admit it. You cannot be a political rebel and expect a career advancement because the establishment prefers the status quo instead of a revolution. Even if you are well-meaning and want to improve lives of other people and society as a whole, you don't bite the hand that feeds you.


But if your conscience urges you to persist in fighting for your ideals, and you refuse to heed grandee's advice, who warn you of the consequences, you will soon be accused of some kinds of isms, followed by newspapers articles describing you as an evil man, and you will sink to the bottom like a ship hit by a torpedo. Communists in the East Europe used purges and fabricated accusation with trump-up charges to get rid of their opponents, while Western democracies have more effective weapons called free press and media which are able to influence the public to believe in anything. They commit hundreds of logical fallacies daily without ever being challenged, and they peddle the same kind of news, while completely ignoring issues which could shake the system and its foundations. Any political leader who plans to radically change society nowadays faces a fierce battle. Not only has he to convince the destitute that he is their friend, but he faces an enemy who is elusive and difficult to see. Don Quixote had to fight against the windmills, but our brave future leader will battle against the shadows, who can order their henchmen to destroy you with a tweet, a newspaper article, fake news, or TV reportage.

 

[Tarheel]

Perhaps:

Many people who became politicians say they went into public service to make a difference. But in the end the only palpable difference they made can be seen in their bank accounts.

Shorter:

Many politicians say they went into public service to make a difference, but in the end the only difference can be seen in their bank accounts.

There's a reason I use "public service" there. It sounds better (has a higher tone to it) than "politics".

 

[Tarheel]

Perhaps:

Some of them come from humble backgrounds and through hard work and perserverance work their way to positions of influence. While they may start off with high ideals, they eventually become corrupted by the system.

The phrase "as soon as" suggests that the changes that took place happened overnight.

 

[Tarheel]

Perhaps:

You cannot be a rebel and expect career advancement. The establishment prefers the status quo. Even if you are well-meaning and want to improve the lives of everyday people, you dare not rock the boat.