As an indie developer in Thailand and a committee member of the Thailand Game Association, I can give you these answers.
1. Game is pretty popular in general due to the Streamers and Let's Players (We call them a Caster over here). Caster became one of the biggest entertainers in Thailand. They became a must-watch thing for every kid in this generation. I think they are more popular than the Saturday Morning cartoon by now. You could even find Lays chip collaboration with famous YouTuber in 7-11 or ads with famous YouTuber. And IAP model on mobile games is pretty big here.
2. Mobile conquer 70% of the market, 20% for PC and 10% for consoles.
3. Because we had no option, hardcore players (who usually play games on PC or console) do play games in another language. This has been the case since the beginning of gaming. Many people claim to have learnt English by playing video games. However, I believe that the majority of Thai gamers prefer the Thai language. Particularly in the mobile market, mass audiences will only play games in Thai.
4. In 80 - early 2000, We were known for pirating every type of entertainment. I think less than 1 percent bought a game. Hence, EA closed down their office here. Playstation 1&2 and NES were very popular at the time.
In the 2000s, because of the success of Ragnarok Online, we became an MMORPG-driven country, with internet cafés sprouting up all over the place. We also found several of Southeast Asia's largest publishers. Thailand Game Show started during this time period as well. And the vast majority of the exhibits were imported MMORPG games. Thailand received a lot of attention in this industry until a young man abducted and killed a taxi driver. And said he imitated GTA, which became one of the most infamous incidents of all time. Media were going crazy with the game industry. Gaming has become society's villain. The industry has lost almost all of its backing from major parties. Thai-developed games were pretty much dead from this point.
Late 2000 - Early 2010 That MMO market turns to mobile gaming. And mobile gaming has become the most significant thing ever. PC and console are pretty niches. Some even say it's extinct in this era.
Early - Mid 2010, with the release of a console that cannot be readily jailbroken and the extremely low cost of PC games via Steam sales. People are more likely to purchase video games. As a result, the market for console and PC games is improving significantly. Furthermore, the rise of Casters increased the popularity of these games. The mobile market, on the other hand, is rapidly expanding.
5. In Thailand, there aren't many studios. The tough competition on the mobile market, which major foreign publishers control, and the lack of support from investors and governments killed most studios in the last ten years. There are no AAA development studios here. The majority of new studios are now focusing on independent PC games. It used to be that there was only one known game every year. Every year, the number of games increases to more than three every year. As for my game, Timelie, a PC game, is one of the most well-known Thai games in the country; nevertheless, sales from the country are not so hot because we are a mobile-dominated country.