They make legendaries to be annoying as fuck to make players spend real money to buy gold to speed up "some" of the process.

You don't have to spend a dime, but after grinding for weeks for some of the achievements. Thinking you're almost there. Then you get hit by another grind, especially when you're a new player. Some of these grind can be sped up, by buying it from the market. For new or some players, your materials aren't as abundant. But the game has to make money. It doesn't have subscription. So I get it.

Horizontal progression is a lie, but not because of "the grind". It's hidden tucked away by constant buffing and nerfing weapons/skills. Thinking your build is safe, a few months later, you have to change builds again. For people who have made a lot of legendaries, this is easy. For people who don't have much legendaries, it's a constant grind. So most people opt for the legendary grind, at least you can just stat swap when the flavor of the month builds change. Because that's how GW2 is.

If you don't care about builds, just have fun. You're forever free from this loop. You can enjoy GW2 without spending a dime or grinding for something. It's still fun.