On the contrary, people in low elos don't actually ever think about turning around a gank 2v3. They see the jungler and lose all their shit.
Usually a winning bot lane can make a jungler's life hell, because often they have the burst damage to kill the jungler before his bot lane can assist him, especially early levels.
Turning around a gank 2v3 happens a lot more than people think. But ofc its impossible to tell without a replay who was in the wrong.
Like let me give an example: 55% health Sejuani is ganking at level 4, you and the support are level 3 and full health. Enemy bot lane is like 70% health, but has to deal with a minion wave.
You have two options, either burn all ur summs just to live, or save ur summs and potentially get a kill or more. It's pretty complex knowing when you can turn it around - because you need a lot of experience in matchups. But by committing to only running, you now give the jungler ALL the agency to try and land a crucial cc or burn your summs, whereas if you the support and AD stick together to turn it around, it can often be fatal for the jungler.
Especially considering most junglers are melee, and you can often get a lot of good damage on them before they even get in range to hit anything. Whereas instantly running lets them close the gap - and now they're too healthy for you to fight.