Anything is hard when you haven't done that before. Be that DMing, making a bookcase, riding a bike, etc. And while you can try learning by just diving into the deep end with zero prep, that is probably not going to be fun for anyone involved. You need to prep, what tools you need, how to use them, how to design, how to finish.
And not every new DM is like every other new DM. I started playing with a pretty darned good DM, when we wanted to start playing D&D with a completely new group, I was the DM. I made my own mistakes (some still very iconic in our group), gave my own twist on things, and the other players learned from me and they made their own mistakes/twists when it came to their turn of DMing. We essentially learned by apprenticeship...
At the end on the 80s, the amount of advice books was limited, we didn't really have the Internet, and the availability of RPG books was extremely limited for us living in the Netherlands. So there were almost no resources, beyond maybe an article or column in a Dragon, Dungeon, White Dwarf, etc. But, we being kids, we didn't have much money to buy all those expensive imports, so our sources were very limited. I don't know how well DMing D&D would have gone if none of us had ever played a RPG before. Probably our best previous experience would have been HeroQuest...
But due there not being the Internet and RPGs being a tiny niche, the expectations were not high either, so we could fail without anyone even batting an eye. These days due to the Internet and the YouTube popular webseries played by actors, expectations are sky high, so high they are unrealistic. It's as if when playing 'cowboys' your acting skills while shooting or being shot would be judged by how well you compared to John Wayne or Clint Eastwood... Now, maybe among friends the bar isn't so high and people are willing to be less harsh, but many folks starting out with randos either in person or online tend to be not as invested and can be harsh or just plain rude when the DM does not meet their unrealistic expectations. I've played with randos at the gaming club in my teens and early twenties, there have been great experiences/people there and not so great experiences/people, but in no case would I have ever thought to be harsh or rude. I was generally quiet, on the younger side in the group, I just watched and learned.
So DMing can be hard, depending on your experience, expectations, your social and creative skills, etc. But just because something is hard, doesn't mean it's impossible or you shouldn't be doing it in the first place. Reading a good book about DMing isn't wasted time imho, but you don't really need a whole collection. There's also many, many YT videos that fill the same purpose, and there are podcasts as well that you can listen to. And people have been selling us stuff for 50+ years for RPG stuff, be it new books, now systems, dice, miniatures, storage solutions, tables, LARP stuff, magazines, subscriptions, etc. This is not new, the hobby is now just bigger then it's ever been and it's easier to reach people through the Internet, so more people trying to sell you stuff should not be a surprise.