Yeah I think the first-party early titles (Excitebike, etc) were definitely more representative of the game play.

But third parties definitely didn't respect this. I'm sure everyone who grew up in this era remembers the infamous Megaman cart by Capcom [1].

One of the things that Nintendo learned from Atari was that massive amounts of shovelware did not help their cause.

As a third party company, you were actually limited to a certain number of games you were allowed to release per year in North America (five I believe). There were ways around that, like Konami forming the subsidiary Ultra.

Additionally they locked the system behind the 10NES chip that made unauthorized game production difficult (unless you pulled the classic Taiwan voltage snap trick or just blatantly copied the source from the US Copyright Office like Tengen).

[1] - https://imgur.com/a/5hUUDnM

It's strange, I learned Forth on the Atari and found that the cover was a surprisingly accurate depiction of how I turned out.

> the first Nintendo games released in the US had explicit images of the game graphics on the cartridges

this is is why the ESRB was created

Yes and nowadays no one would even bother put in that much effort. They would have an AI generate the box art and the jokes. The jokes wouldn't even be funny, but no one would care because "human jokes aren't usually funny."