Newbies shouldn't be diving straight into an event from the start to begin with. Doesn't mean they're actually barred from it.
There's a difference between being newbie-friendly and walling newbies from new content. You're suggesting it's the latter and want it to be more like the former. I'm suggesting that it's only the former, assuming the player actually does research (and the player isn't super-unlucky to never get a drop).
The difference is that making the game too newbie-friendly dumbs down the entire game. If all events were as mind-numbingly easy as the gold rush (sans Bernice's map), we'd have a lot more problems with the fundamentals of the game.
Btw, I'm pretty sure you're playing down the RNG. I got 10 copies of the event unit solely doing map 4, and on previous events, I know a handful of people who could only afford to farm the lower maps and usually still get by with at least one copy. It's far from impossible, especially if you can run the lower maps twice as much as the higher maps. Yeah, they'll obviously get less copies than if they were able to do the later maps, but getting a single copy over the course of a week? That's not a tall order.