For lawmakers to allow medicinal use while actually planning for eventual recreational use once "society is ready" is unprecedented on this planet is it not?

That depends. It might be if you mean that they legalized medical specifically with the plans of legalizing recreational. However, many nations have legalized medical use with the intent of legalizing recreational down the lines. Including Canada, the second country to legalize recreational use after Uruguay. In Canada, it is said that the conservative government legalized medical cannabis in order to build up the industry as the world tended towards legalization.

What is interesting, however, is that Thailand is located in SE Asia which isn't exactly known for lax cannabis laws. Furthermore, as another commenter rightfully pointed out, they are lead by a military dictatorship. So, while it is Thailand, known for issues with slavery, prostitution, and a lively nightlife it still comes as a bit of a surprise really.

It's looking very much like the worldwide prohibition of cannabis will go away and the drug will start to look a lot more like alcohol. It'll be very interesting to see who the hold outs are but I imagine they'll be mostly in the SE Asia and perhaps a few in the middle east.