Why Doesn't League Have a Safe and Off Lane Assortment?

In League, it is much easier to get ganked Top Lane when you are on Red Side and Bottom Lane when you are on Blue Side. This is due to the fact that there is two openings in the Jungle in between your turret and the middle of the lane in the respective lanes for each team. So why doesn't the ADC and Support for Blue go Top and the solo go Bottom? It's not like there is no chance the solo laner wouldn't survive so to speak. There are several champions now days that can easily farm by poking or just be in general resistant to damage and still get farm appropriately that still provide what Top Lane is expected to bring. See:

Is this just because of Dragon or what? I feel like Rift Herald is fairly strong objective that would be heavily rewarded if the team focused on using it.