This may have escaped Marvel's notice, but they are in the business of selling stories and entertaining readers. The current level of adverts displays an arrogant disregard for the quality of their product. The monthly pamphlet is a format with little to recommend it. It is slow. It is flimsy. It will unavoidably carry adverts. About the only thing it has going for it is that it comes out before the trade paperback; if it were the other way around, I wouldn't go near the things.
If you’d only told somebody this in 1935, we could all have saved ourselves a lot of time and effort.
If you don’t like that format, there are always others that you can buy–collected editions, as you say, or digital copies, for example. Or you can choose to buy none of it.
But really, you’re upset because there are ads in the comics?