I think that this is modeled incorrectly. As voters of a group are made happy over a long time they shouldn’t accumulate negative opinion, they should lose membership.
Let’s imagine a voter who drives to work through congested traffic in an obviously heavily polluted city. If this voter isn’t blind they can see the haze in the city air, see the blue river turn brown through the city, and notice that their persistent cough slowly goes away when they go on vacation, and comes back when they return to work. They also know that their commute is a 20 minute drive off hours, but takes 90 minutes each way every day.
This voter is likely to be found in the environmentalist and motorist voter blocks and is likely unhappy for both reasons.
Now, let’s say that the government implements strong pollution controls, bans coal burning, subsidizes green energy production, regulates water consumption, sponsors electric car programs for a few years before banning the sale of petroleum powered vehicles. The environment will likely clear up. The haze will clear, the voter stops coughing, the local news is pointing cameras at the marine life returning to the river in the city. This voter isn’t going to think “it’s been too long since the government did something for the environment”, they’re going to forget that they have opinions about the environment and fixate on the 90 minutes each way they spend in the (now electric) car every day, and continue to be pissed off.