It use to be that if your top or mid lane died early on, either to a gank or a 1v1, you could simply farm the wave and make the gold advantage just a little bit less.....
Now if your team is doing poorly, you will easily have the most gold on your team, and even if behind, will get absolutely no catch up gold from farming a lane of a team mate that just fed the enemy gold. Honestly it is probably the least thought out method of fixing the funneling strat.
New fix:
Jungle items
Passive
Monster Hunter: After killing a Large or Epic monster, lane minions are worth X less gold for 30 seconds.
Tada, now you can't farm both, but you can choose to ward the camp, catch the wave, and not get put behind for doing something that should put you ahead. ( Put behind because of time investment, which means lower GPM ( Important stat ) and because of risk of camp being stolen while covering lane.