Within 90 sec, you gain 400g from minions(9 range, 9melee and 1 siege) IF you get ever single cs. if we asume 1 minion missed per wave, it's 3x20 less so ~340g
Within 90sec, you can clear all small camps once for a total of ~370g, not inclueding buff camps, scuttlers or what ever you could get in the opposing jungle.
So by just farming your own small camps as soon as they spawn, you already can earn more gold than a sololaner with near perfect cs.
And a well played shy will not only clear her own jungle in that time, but also scuttlers and usually succesfully counterjungle.
Same with nidalee.
She has the highest Counter Jungle CS and the seconf most CS in her own jungle amongst all champs and more average gold earned per game than Anivia....
For most junglerrs you are correct, though 'double to three times more farm then junglers' is vastly exeggerated, unless you mean only the number of cs rather than the resulting gold.
Most junglers don't clear/path fast enough to get all camps within 90 sec, mostly because of the time they spend on ganks, lurking for counterganks and other stuff. And there is the potential of getting counterjungled. In the jungle, you can actually directly deny the cs of your opponent.
Also, i said nothing about shy beeing strong overall though she does perform decent atm, a solid 50% winrate in the jungle with ~57% on experienced players, which is above average. I said whatever strength she has right now, is caused purely by her clearspeed and the resulting gold lead. And in xp, she usually is even or ahead of the soolanes.
Her kit it's self is rather weak atm, as soon as she has to fight on even gold/xp, she usually struggles, which is why her toplane is so bad, as she hardly will get a meaningfull xp/gold lead over her opponent since she has little killpresure in lane and can't just powerfarm for a lead, as her opponent will usually get about the same farm.
So in the end, the only reason she currently is viable is her artificially increased clearspeed with the 20% bonus damage vs monsters on her W.
But instead of removeing that and giving her the buffs she actually needs, they keep that and tinker around with half assed buffs that don't make her any more statisfying to play nore help her sololane, because they are afraid her jungle might get to strong again....
then. the had removed his passive stacking on his ultimate with the mage update, but added it back a couple patches later.
. 1 shot kids. Profit.
is a noob trap and there are much better items on her. Honestly you don't even need Trinity force because the damage with 3-4 health item Titanic Hydra plus your already insane attack speed means you're a tank that chunks hardcore.
gives special bonus experience but why is that? its is cuz a jungler has less gold resources and income then laners. hence why a champ like 
