To takes some of the mystery out of it, there is something called ZEV, which you may or may not have heard of, it stands for the Zero-Emission Vehicles program first started in California and now adopted in several other states including Connecticut, Maine, Maryland, Massachusetts, New Jersey, New York, Oregon, Rhode Island and Vermont. It's a complicated program, a very oversimplified explanation is that each car manufacturer is required to sell a certain percentage of plug-in cars compared to their total sales volume in that state. The method used is actually "credits" of varying amounts which are earned for each car sold, but for simplicity just think of it as a percentage of cars sold. The states allow a portion of the plug-in cars sold to be PHEV vehicles like the Clarity to be counted towards the requirement. If the car maker falls short they pay a huge penalty, so they make sure they sell enough in those states to meet the minimum requirement.
In addition the car makers usually offer big cash incentives to buyers in those states, and the states themselves often have tax breaks in addition to the federal one, so that tends to keep cars flowing off the lots and makes it take even longer before they have enough of a surplus to start shipping cars in any appreciable quantity to the non-ZEV states. The unconfirmed assumption is that the car manufacturers don't make a big profit on these cars and they only sell as many as they have to to meet the requirement, which is presumed to be one reason for the lower quantities and lack of advertising.
Recently in Georgia and NC they started really dropping the prices on 2018's, probably this indicates that they will start getting a larger quantity of 2019's soon. So if someone really wants a 2019 they probably just need to wait a couple more months or so, although it will probably be hard to get a discount while the 2018's are still on the lots.