Cost is a huge factor but so is charging. Tesla is the only one that has a good infrastructure, everyone else seems to be dragging their feet. The Tax credit is nice, but it you'd really don't save anything because you're going to need to install a home charger for a EV to even come close to breaking even over a gas car. That's assuming you live in a house and not an apartment building which doesn't have any chargers, so you're dependent on whatever charging network is near you, which for me and my area i'm 30m+ from a non Tesla charger.