Putting resources by China in Cambodia, Myanmar, and Pakistan is one thing..those are nations that was, and is increasingly dependent strategically for their defense with China. However China betting high to lure Thailand to build cannal in Kra peninsula is something that I think bit too risky for China so called 'string of pearls' strategy.
Granted there is significance commercial insentive for Thailand tobuild Kra Cannal. China wants to invest heavely on something that can by pass Strait of Malaka..can be worthwhile if China can depends on the Cannal host. However Thailand is not like Cambodia, Myanmar or Pakistan in term of dependency to China both militarily/strategically and economically. Granted China trade and Investment is big for Thailand..but like for Malaysia, Singapore or Indonesia..China trade and Investment is something that can be substitute much easier by those countries relative compared to Pakistan, Myanmar or Cambodia..
In short like the rest original 6 ASEAN, Thai dependence to China is something that can be substitute..not like the other 3 that mentioned earlier. By passing Malaka Strait thus still a problem that China still can not have clear strategy to do, besides neutralise all Indonesian, Malaysian and Singaporean Navies in the situation when hostility erupted.
Before somebody say that China navy can easily neutralise combine strength of 3 Asean Navies that controlled Malaka Strait..well it backs to reality..if hostility break up..and China Navy need to pacified and controlled Malaka Strait..do any body seriously think that those 3 Navies are the only thing that will stand in China Navy way to control Malaka strait ?
All this back to the present action China in SCS..and so called 'string of pearl' strategy..all this back to China ability to coerce and persuaded its SEA neighbours...and not antagonising them..