Out of state buyers came in and pushed up prices. Vacation homes in RI are a bargain compared to other places. Covid remote working allowed others to come to RI because houses were cheaper than where they were. Covid also saw people spending lots of time at home move if they wanted more space at home, or renovate their homes, so a lot of home sales that would have trickled out into supply were kind of rushed into it, so theres no backlog of homes to come on market or if you renovated you are staying for a bit. The high prices and high interest rates makes it so everyone that didn't buy recently have a better situation than what they could buy into now so they are staying put. Rates are still high, but prices have backed off peak a bit so anyone thinking of selling now missed the high point and will be less likely to sell. The only people moving right now are those who have to for some reason, like work.

Lots of reasons really. The market will work itself out, but not any time soon.