As I already said, it's an uncommon magic item in the core DMG, is slightly stronger there than it is in this game, and it shows up on the lowest grade of treasure pulls, designed to be found by level 1-4 parties. It's a low grade magic item; it's not especially valuable. I'd thank you not to back-handedly call me a liar over something you could very easily fact-check yourself in a matter of seconds.
5e did take away some of the greatest powers behind a high intelligence score, indeed. You no longer get more skill points from higher INT because they maimed skills with proficiencies and you don't get more spell slots from INT but rather just more spells to choose from.
