If you knew the licensing trail you would understand why for free viewing there are commercials.
Know that Asian dramas have gained so much popularity that their actors are getting more paid, some dramas are getting more elaborate, the networks are asking more money as well.
Today's expenses for everything are rising.... no wonder licenses are getting more and more costly, also because of streaming competition the single rights are the most expensive. Plus the entire IT team and business team including large servers and maintenance.... it's all money here money there... you'd be surprised what all today costs, which has to roll onto consumer like any other product.
Whether you buy a laptop, a bicycle etc. there is the self cost plus profit margin, that's the end price we consumers pay. I personally hate ads and do not watch them, a reason I gave up a TV cable/channels longtime ago. - As a consumer you have a choice.