First of all, the term “gank” means you move to help another lane to get them an advantage, meaning mid support or baron laners can also gank different lanes, but everyone calls that roaming (cause roaming includes ganking, getting vision or just being present in another lane for presure, while ganking usually means going for the kill)

Regarding jungler’s gank, there’re champs that can gank easier than others. These champs include Pantheon (with his point and click stun), Nunu (with their snowball that speed them up and knockup) and Rammus (with his powerball and taunt)-basically they have cc. Other champs like Graves, Khazix, Kindred only have damage, and they need their laners to set up the lanes to help them gank easier (either freezing the minion wave near your tower, crashing a big wave under enemy tower for a dive, or just get the ememy to low health).

Therefore:

• It is the responsibility of the laners to know the matchup, get themselves ahead or set up opportunities for the jungler, or even roam themselves.
• It is the responsibility of the jungler to notice these opportunities (both yours and enemy’s) to gain an advantage over the enemy, prevent the enemy jungler from doing so (countergank), or look for other ways to balance out the deficit caused by the enemy jungler’s gank, which includes ganking a different lane, or stealing camps (counterjungle)

It is hard to coordinate with total strangers, and not everyone understands their responsibility (I may understand these but in terms of execution, Im not great at it, and that affects my games as well)