I don’t think either country can sustain a ‘war’...more than 4 to 6 weeks. In Thailand’s case...it’s scaring the crap out of tourists with reservations.
China effectively owns both Laos and Cambodia. Thailand, like Vietnam does not like nor trust the Chinese.
Belt and road is big in Laos and Cambodia. When I was there in 2020 China was building a railway through both of them to the Cambodian port China owns.
Do not underestimate the Thai people.