Jungle entails farming just like with any other role. Farm = getting ahead or keeping up in gold and experience.
Jungle entails warding just like with any other role. Lanes ward to prevent ganks. Jungle wards for similar reasons, but also to prevent enemy counter jungle or to enable counter jungle against the enemy.
Objectives are often a team effort. If there is no map pressure then taking dragon and what have you becomes a severe risk. That means warding, map awareness, and team cooperation. You don't need allies present to take dragon. It is often enough for allies to keep their lane opponents occupied while farming safely and staying healthy enough to help prevent an enemy from roaming.
Then there is ganking. Killing enemy champions does not award a lot of exp. Assisting in an enemy champion kill does not award a lot of gold. Jungle camps collectively are more valuable in gold and exp than killing enemy champions.
The value of killing an enemy champion is not weighed in how much gold you obtain, but how much gold and experience you deny that enemy by removing them from lane. If an enemy is forced back then it's good enough and chasing them down under turret and unwarded terrain to try and kill them is counterproductive.
People will get upset at you if you don't gank. People will get upset at you if you do gank and your team gets no kill out of it. People will get upset at you if you gank and get the kill. People will get upset at you if you gank at an opportune moment while they're still farming. People will get upset at you if they ping for help, you offer it, and they still end up dying because they expect you to travel thousands of units from top to bottom and vice versa in an instant.
Ganks, however, are not the sole responsibility of the jungle. The jungle is a roaming farmer, but they are still a farmer like any other champion on the map. A gank is nothing more than a group fight and anyone can join in on one. Anyone can start one.
To expect constant ganks from the jungle is as ridiculous as mid expecting the bot lane ADC to stop farming five minutes into the game to come over and kill the enemy mid for them.