Just to play devils advocate for a bit, but all of the evidence you've given is based on one culture,
how do you know that legalising drugs in other countries will give the same effect?

Also regulation can be ineffective (notably taxation), for instance increased taxation of fuel has
hardly stemmed the use of it (I appreciate the flaw in this argument ), or the increased taxation
of alcohol?

I am actually in favour of legalising (some) drugs, just a bit sceptical about how effective it would be.