i play quite a bit and i can corroborate that this theory is more or less real.

This is how i farm e.g. 5 hellskulls in a single game ........ not to mention other dupe loot. this becomes more apparent when your not only getting dupes for 1 item, but multiple items ......

so the strategy is, if you confirm something in your existing game's loot table, you then farm that game likd mad e.g. rifting and spend shards on that item type until you get it.

sometimes i can gamble kadala for 5 shields within a 3-4 hour span. somtimes it takes a whole day for the item to drop e.g. akkhan glove set item 

also dependent on your rng :[ even if you do know something is in your current loot table.

another curiousity is outside that loot table there is also a chance to get loot outside your own class .... i think this is a totally random variable    not really sure if it applies to your own class as well to some extent ...
currently i'm hunting witching hour, but i'm finding it hard to get it in my loot table. i rift and gamble to check if it's there, but no luck :{ my rng is bad.

This morning...bliz give me Falcon Foote...
Now trying reroll socket...
But no sure...will it better..I mean DPS....
If not, I dont want waste my money & etc to enchant...
By the way...my DPS now 1.3M...

Talk about being luxky .

dont bother looking for a higher dmg falcon, urs is at the highest dmg it can naturally roll. Unless it comes with a socket.

mine is only 1933 dmg with no socket. Roll socket instead of dmg.
Ur jekang oso very good it can hit 6 targat whixh is the max, i got 4 jekang but it only hit up to 5 targets.