Century ago United States tried to ban alcohol, and it simply didn't work - it is way too easy to produce it from innocent food products. Exotic mushrooms or artificial drugs are much easier to ban.
Some species like Psilocybe semilanceata grow in the wild, both in Europe and North America. You can just pick them if you know the type of habbitats to look for.
You can buy grow kits semi-legally (grey area, might vary on where you live) and you don't need any extra equipment. You get a plastic box and you literally just add water.
If you want to save money, you can buy only the spores. Then you just need some substrate which you can buy either at garden supply store or at a supermarket. Biggest issue is ensuring sterility, so a pressure cooker is recommended, but there are ways around that.
I'd say it's easier to grow shrooms at home than it is to make alcohol. You don't need any specific equiment like a still for distilled drinks, and you don't need any trial and error like you do when making fermented drinks. I know you could make alcohol without any equipment, but the end result will probably be quite poor. Meanwhile the shrooms grown without any equipment will be the same as any.
You can ban them, but your ban won't be any more effective than the ban on alcohol.
It's easy to get pretty much any drug you want.. especially in Amsterdam.
All the ban does is moves the market underground, gets organized crime involved, makes it much harder for users to tell they're getting what they paid for (possibly leading to all sorts of adverse effects like overdoses), and ruins people's lives when they're thrown in jail.
We know drug bans don't work and are counterproductive.
It's sad to see the Netherlands buy in to anti-drug hysteria after being one of the leading lights in constructive drug policy and harm-reduction for so long.