The experiment isn’t to make weed sales legal. The experiment is to make growing weed commercially legal(-ish). The sale has been legal-ish since the 1970s already.

Technically weed is not legal, but sale, posession, and growing for personal use have been officially tolerated (gedoogbeleid) for decades. They are effectively legal in anything but name.

Growing weed for non-personal use is not tolerated. But it is tolerated that the coffeeshops which are allowed to sell weed, buys weed from these illegal growers. Its the one major hitch in our drugs policy, which many believe doesn’t make any sense.

So this experiment is meant to create a way for companies to grow weed in a way that will be officially tolerated as well. And we just reached the next stage of that experiment where coffeeshops in the participating cities are no longer allowed to buy weed from illegal sources.

This can lead to official legalization of weed. But that would effectively not change anything in practice, compared to how things are run already.