I have gotten Legendary items from the Wasteland but most of them have come from the National Guard Depot event at a little past 60 hours of exploring ... however, the hit rate is not high so the best way to get Legendary items is scale (I have 49 dwellers with all 10's in SPECIAL exploring now) ... I seem to get 1-3 Legendary items for each round trip of the 50 explorers ... if you were running fewer than it could probably take multiple trips
the last 3 lunchboxes ive opened had 500 caps as the rare item. so disappointing! I have 999,999 caps already! take the caps out of the lunchboxes please!
This here is the #1 reason I do not ever buy lunchboxes. 500 caps is a ripoff of a rare item and happens way too often. "Rare" should either be a high-quality high-end gun/apparel, a legendary gun/apparel, or a legendary dweller. Something that isn't an ephemeral consumable.
I can confirm that you can get legendary weapons and armor from the wastes, I have 24 max level, max stat explorers with at least rare armor constantly exploring and Ive found a fat man, couple mini guns, and a missile launcher as well as a couple sets of power armor.
Tthe drop rate as far as I can tell is extremely low and due to the encounter log being pretty short I cant pinpoint at what times these discoveries took place, apparently theres some link between an event at the national guard depot around 3 days exploring that has a higher chance to get legendaries, but I havent confirmed this for myself.
Just keep trying, sift through the trash and hope you get lucky.
I also can confirm legendary weapons from the waste although this did not start happening for me until I had over 30 explorers out at a time. I will also confirm the 60 hour National Guard depot event is a good chance for getting rare or legendary items but not essential. I received 2 sets of power armor 5 minutes apart both within 10 minutes of exploration from 1 MAX STAT dweller and the other completely untrained from a radio call. Another post put it right which stated the theory of quantity over quality regarding your dwellers being sent out. Now with that said I currently have over 50 MAX STAT explorers and they all on average get combat shotguns, Laser rifles, gauss rifle and railway guns in each exploration, so training still is essential if not deeply flawed still. On a side note you must be patient if you are wanting to earn everything over buying outfits/weapons. I am almost at the 4 week mark of gameplay and I just now received my first 2 missile launchers 1 hour apart from each other (1 found in the wasteland and the other earned in a lunchbox). Hope this helps!
You are definitely more likely to get legendary weapons than legendary outfits (at least in the current version) ... I have gotten multiple weapons with 20+ damage and tons of weapons with high teens ... my outfit finds are fewer for rares and I haven't been monitoring close enough to see if any of my legendary outfits came from the wasteland