Sure, that is fully possible, and as Itsari post even possible at 15k baht per month. However, one does not have to be a drinkers to spend more. For myself, it goes a bit as I am found of beer. Not alcoholic in any way as I have a lot going on with work on a daily basis.
Other things that can cost, are if you like a more exclusive lifestyle. As OneMoreFarang posted, it can be good coffee, variated international food. Maybe some have a desire to go out eat a lot, as they might be bad at cooking. Shopping can take a fair amount of 1000nds per month. After that, I work totally remotely, so we like to travel on weekends, which means hotel and other things.
So, just because some of us here say that we spend 70-120k baht per month, does not mean we wish to boost as the posts almost always are posted in thread like this. In other words on-topic. We just have the means to live a little bit better, while some of us also save a lot on the side at the same time.