I think your argument is off by about 10 years.
The Legend of Zelda on the NES hailed from an era where you weren't even remotely expected to beat the majority of the video games that you owned. Pokemon Red & Blue absolutely did not belong to that same era.
I also think it's too reductive to reduce this aspect of 20th century game design to a negative "guide-dependent" argument in the first place. One thing that's kind of been lost to time is how single player games used to also be social experiences. Like, real-life, analog social experiences. If you got stuck in part of a game, one of the first things you'd do is talk with a friend and ask what they did to get past it. This is more or less the real definition of a "metagame"--the game outside the game. Collaborating on an adventure could actually add something of value to the experience, make it feel more immersive. It was fun to share secrets and strategies that you found with others. There was a case to be made that the need for the player to create maps for something like Metroid or Phantasy Star in order to keep from getting lost wasn't "busywork," but a substantive consequence to make the experience more meaningful, and sharing those notes with friends was enjoyable, made it feel like you were accomplishing something bigger through the act of working together. It was a huge part of the appeal of games like Myst, which were incredibly cryptic and sparse on purpose, and which using a guide for would
completely kill the appeal of the entire game. When modern Dark Souls fans talk about the value of collaboration and community strategizing to beat difficult bosses, it's sort of cut from the same cloth of what I'm taking about. (And as an aside, it's also part of the reason why I often find Souls fans to be insufferable. They tend to have no perspective of video game history and will gush nonstop about how "revolutionary" some component of it is when it's just derivative of something that's been around for 3 or 4 decades. You can draw a very clear through-line from
Tower of Druaga to From Soft's catalog. But that's all beside the point.)
Anyway, I dunno how best to articulate that Pokemon Red & Blue really wasn't all that difficult to figure out when it was new, especially compared to the older stuff I just mentioned in the previous paragraph. It has very little resource management compared to so many of its predecessors, no equipment/weapon/armor component, and battles that are strictly 1v1 at all times instead of involving an entire party's worth of actions for each turn with all of the tactical team/attack synergy that such systems could offer. It is nearly maximally a "baby's first RPG" as an RPG of its time could be. Part of the whole reason why it was one of the first Japanese RPGs to catch fire in the mainstream American gaming populace was
because it was more approachable than most! The link-cable trading/battling component of the game also made it much,
much more relevant to the communal nature of video games than anything else I outlined above. Pokemon has been a "press the A button to win" game since its inception; some players just had to grind more to get it done because of their inexperience with RPGs at the time. I was there. Not only did I not need a guide for it, but I could almost beat the game on a single session, and the only reason why I couldn't at first was because my first exposure to the game was from borrowing a friend's cartridge and being absolutely forbidden from saving over his progress, so I basically just approached it with a speedrunner's mindset to squeeze out what I could before either the batteries died or I had to quit and do something else.
It's why I usually find it a little funny whenever somebody bemoans how "dumbed down" the franchise has gotten over time. Yeah, sometimes there's some truth to that and sometimes I also have gripes with specific changes, but, like, part of the reason why you feel that way is because you also just didn't have a very good frame of reference when you were 7 years old or whatever.
Kanto is not obtuse by 1990s RPG standards.