The rental management companies seem like they are getting the attitude they can get away with it so they will.
Owning (and prepping/outfitting) a cottage that (not everyone, but many), during the rental season, "holds" the party of the millennium every week and is subject to renters "it's a rental, WTF cares?" mentality is not just collecting "mailbox money".
Business practices such as thirty or forty percent price increases, nonrefundable fees, and pressuring customers to book two years in advance will only worsen the entitlement attitude that some owners complain about some renters having. Not suggesting that justifies any renter abusing a place, just noting that less-than-savory behavior sometimes begets less-than-savory behavior.
Having said that, I have rented on HI regularly for twenty-plus years and continue to have positive experiences, but like most older persons see things changing in ways I think are not positive. Prices have gone up more than I would like, but for the small (3 bedroom) homes my wife and I rent in the fall and spring, I have not seen the types of increases some others have complained about. I am more concerned about the increasing crowds. That, more than the price, has me seriously considering if I'll return beyond 2022. We usually (not always) rent from Midgett and have found them to be fair and professional. Most years we rent a different cottage for the variety. Years ago, some homes had guest books that were fun and provided a connection between the renter, other guests, and I'm assuming the owners. A couple of times I received a Christmas card from an owner. That personal touch seems to be long gone and now it's all business. People simply aren't as thoughtful in purely business relationships as they are in relationships with a personal touch. Today you can rent a place, check in, spend a week or two, and check out without ever talking to another human being, unless you consider a text or computer-generated email talking. All that makes it easier for the renter prone to bad behavior to not consider that their actions are impacting another person. Again, it doesn't justify bad behavior, but the de-personalization of the process and "business-only" attitudes are not improving things.