Losing lane in a 1v1 or 2v2 scenario is entirely their own fault. Now, losing lane comes down to a lot of factors such as matchup and skill (picking a scaling vs early game bully).
Junglers have the power to skew lanes in their teams favor through applying and relieving pressure.
Junglers can easily unintentionally make their allies lanes harder when they think they're helping, such as taxing XP (waiting in lane brush for too long), shoving or pushing minion waves into the enemys advantage (setting a slow push to the enemy tower where they can freeze It), or not recognizing the opportunities available to them.
The more laners understand about minion wave management, the more they can help junglers out in their job.
If I'm top lane, I can recognize when I can set up a freeze closer to my tower and call for a jungler gank a minute in advance "Hey finish that camp or two then come top, free kill," or pinging when their flashes/sums are down. If the jungler refuses to take advantage of this that's fine, but I'd hope they make use of the time better than taking just taking a camp.
My personal advice and opinion on junglers (from an ADC main) is they should help the snowball of winning lanes. Gank a lane, force sums, and return within the next few minutes. The pressure that you apply to that lane will spread further through mid game rotations than the losing lane could ever do by getting help to just go even.
If my jungler refuses to gank botlane but they get top lane fed, top lane can shove to roam mid, paired with jungler as a 3v1 gank. TP bot for the fiestas. Ganking for the bot lane into taking the first tower should lead to a rotation of botlane going top and taking a 2nd tower, or a dragon.