I believe that happens because they refuse to go outside of their roles willingly. There is no excuse to not be able to at least hold your lane well enough to get carried. Every player should play other lanes to some extent. They don't have to be excellent at it. They just have to not utterly fail.
Mid needs to keep wards around either side of river and look for roams. Mid is like a second jungler / support. Top needs to pressure the tower and look for tps while keeping riv and tri bush warded. Adc should be focused on farm and staying in a safe position hitting whatever is closest and strongest or squishiest without getting caught. Support needs to be map aware and warding / deeping warding + pinging movements.
The jungler is focused on rotating and grabbing objectives, they should farm jungle while going between ganks, and keep lanes pushed. The jungler also has to realize which laners will carry when you feed them. Saving a losing lane most of the time isn't worth it. They'll just throw away the lead or you'll just get counter ganked into a worse situation.
Jungle turns frantic when all the laners fail. I like to say its putting out fires with a cup of water. Your more likely to get burned than redeem it when a bonfire has already started (Feed trying to save the game). Sometimes it could of been stopped before it got to that point. Other times you just have to take the loss.
Just assume when you're laning that your jungler will never help you no matter what and things typically will go smoother. I'll say from playing Mid lane 90% of the time they won't even if it's a half health squishie at your tower. So play the lane like its a 1 v 1 that has 4 other players ready to help your opponent. That is, if you don't have vision on their full team then assume they're probably going to gank you.
PS: If you see a on the way ping from the jungler look at your map he's going to be ganking. Be ready to set it up or follow up. The map is a lovely tool. Look at it every 2 seconds!