I'm not sure if you're seriously recommending a return to alcohol prohibition or if you're using it as a sarcastic counterexample to my point. However, in either case my answer would be that alcohol is still significantly different than meth and PCP in how dangerous it is, how much demand there is for it, and how easy it is to make.
1. As we learned from our first attempt at alcohol prohibition, it's just not worth it. The black market violence ended up being worse than the violence caused by drunks and so many people were willing to defy the law that it was unenforceable.
2. Some people who drink are more prone to violence. Some people who drink will disregard their impairment and drive anyway. All people who take meth and PCP suffer from paranoid delusions, will commit crimes to feed their addiction (or commit crimes due to their psychosis), and cannot function as normal members of society. An alcoholic can satiate their addiction without ever getting drunk. A meth addict cannot satiate their addiction without putting themselves in a multi-day state of psychosis.
3. One has to consider the practical consideration that we live in a (supposed) democracy and banning alcohol would be extremely unpopular while banning meth is extremely popular. This is one reason why federal marijuana prohibition is so galling—it's in direct opposition to what the people want. Demand is also an important factor when considering the practicality of prohibition. There's a much higher demand for alcohol than PCP, meaning there will always be a black market for alcohol whereas the modern black market for PCP is negligible precisely because demand isn't high enough to take the risk of production and selling even for most existing black market sellers.
4. Alcohol is extremely simple to make. Humans have been making alcoholic beverages since at least 10,000 B.C. It's so easy to make that prisoners make it in their toilets. Hillbillies still make moonshine even though they could just go to the liquor store. Beer brewing is a common hobby for middle aged men. The ease of production is a major reason why alcohol prohibition proved to be so ineffective. Meth and PCP both require knowledge of chemistry, special equipment, and obtaining other hard to acquire chemicals to produce. As with pharmaceutical drugs, the difficulty of production makes regulation easier.