Oh, don't think for a moment some people would not like to make alcohol illegal. For the record, they did in the US in the early 20th Century. The 18th Amendment to the Constitution of the United States of America introduced the brief era known to history as the Prohibition.
During that era it was not only illegal, it was outright unconstitutional to manufacture, import and export alcohol as a drink.
The Prohibition was the biggest flop in American legal thought: The idea that you can legislate morality.
It did not work. It gave birth to organized crime. It became the biggest embarrassment of US political structure. And US population (since it was an amendment to the Constitution, it had to be approved by the people). Soon it was overturned. The US is not going to make the same mistake again.
That does not stop US politicians to make other mistakes, even similar mistakes. Well, at least illegal drugs are not unconstitutional.
Personally, I have never used any of the illegal drugs. I would not use them even if they were legal. I think they should be legal. Not because I approve of them but because I believe there is a fundamental human right to do dumb things.
Besides, legalizing these drugs would take out profit from their distribution. We have too many people involved in the war on drugs. We have too much drug-related crime. In my humble opinion, legalizing drugs would bring about many problems in the short term, but would be beneficial in the long run. The drug usage would decrease considerably because there would be no drug pushers.
I think the main reason drugs continue to be illegal is because most politicians are embarrassed to admit they made the 18th Amendment mistake for a second time. And if not embarrassed than scared: Unfortunately, in the US for a politician to admit to a mistake is a one-way ticket to retirement.