The main problem is that, even more so than the past, people's politics is their identity.

It's their family, their church life, their friends, and possibly even their neighbors if they live in a particularly conservative area. The same is true for liberals.

Trying to change them is quite literally like trying to change how they were raised, who they associate with, etc. In some cases, they may even be ostracized for "changing sides" if people found out.

It's just not feasible.