@Bob *********
I think your view is heavily influenced by your previous experience with the ED visa system.
Nobody is granted a DTV under the Soft Power category to study for five years—that would not make sense. By the same logic, the Workation category should only be issued as a Non-B visa tied to a specific employer, and if the employment ends, the visa should be revoked. However, that is not how the DTV system operates.
Thai embassies issue a DTV to applicants who meet the eligibility requirements. The visa allows entry for up to 180 days per visit within its five-year validity period.
For example, if an applicant states in the application that they intend to stay in Thailand for 150 days, they must demonstrate that they have sufficient financial resources to support themselves during that stay. In addition, they must show that they either qualify under the Workation category or are participating in a legitimate Thai government-supported Soft Power program for the period stated in their application.
No applicant states in their application that they intend to remain in Thailand continuously for five years. Five years is simply the validity period of the visa, not the duration of a single stay. An applicant may enter Thailand for 180 days, then spend the next four years in their home country or elsewhere, and later return for another 180-day stay before the visa expires.
Therefore, it is not accurate to argue that a six-month course cannot support a five-year DTV. Using the same reasoning, one could also ask how the government can issue a five-year DTV under the Workation category when a person may only work remotely for six months or may even leave that job shortly after the visa is granted. That is simply not how the DTV framework is designed.