That's the point. Drugs were suppose to give up great bonuses with horrible side effects. If you played Fallout 1 and 2 you would know this.
In Fallout 1 and 2 every drug except jet was incurable you'd have to wait about 7 days for the side effects to wear off. Super Stimpacks even cause you to lose health after awhile.
Jet on the other hand is permanent until you find a cure. If you're lucky you may find a cure halfway through the game. It took me like 2 in game years until I found a cure for jet.
It's not stuff game design it's role playing game design, go and play a REAL role playing game and then come back. (Oblivion, Skyrim, Fallout 3 and Fallout 4 does not count as real role playing games.)
I'm not sure what playing Fallout 1 and 2 have to do with the chem systems in New Vegas and Fallout 4 but nice pot shot at trying to invalidate me. I don't know if you noticed, but Fallout 1 and 2 were played in loving isometric views. The combat was basically turn-based. Their game-play styles were beyond 
unimaginably different from the following 3 titles. It's called innovation. The mechanic you are describing revolves around an 8 minute boost that has a chance of a negative side effect lasting 
the entire game (jet in particular). This is a description of a severely unbalanced feature and I'm not sure what grossly unbalanced features have to do with RPG's, or how they make they make the game better or more hardcore. Fallout 1 and 2's chem system worked in Fallout 1 and 2 because the entire combat system was handled by the game in the form of a bunch of numbers. In Fallout 3, New Vegas and (particularly) Fallout 4, you have a crosshair. It's time to move on.
The 7 in-game days thing makes sense, but what would stop somebody from just loving going to sleep for a week? The chem system could use a nerf I agree, the addictions can be cheap to cure, but none the less you still have a chance of getting a negative effect EVERY TIME you use a chem which can stack up against players who use them often. Not to mention putting you at a disadvantage in the middle of the wasteland. Sounds to me like a pretty good example of negative side effects (without having to be a big loving nuisance). If anyone had a legitimate reason to change the chem system, I'm sure they easily could.
And yeah, I don't know, I've played your RPG-waifu New Vegas for 117 hours with many, many different characters and so far I'm convinced that your idea of "role playing game design" isn't really 'design' at all, it's just a bunch of hamfisted tweaks based on your personal opinion that fake difficulty is a good thing.
Winners don't use chems.
I don't think 
anyone would use chems if you had your say in it.