Bit of background first, US citizens and US companies can own 100% of a Thai company, the rest of us can only own maximum 49%.

 

https://en.wikipedia.org/wiki/Treaty_of_Amity_and_Economic_Relations_(Thailand–United_States)

 

My question is this, how come other major trading blocks, particularly the EU, have not negotiated an equivalent treaty so that their companies and citizens can own 100% of Thailand companies same as the US? Is it incompetence, weakness, not wanting to rock the boat, or something else?

The US is in it's own class, it's not the EU or even the UK.