While Progressive & Geico have tow coverage, read the fine print. It could have a limit of covering tows up to $300 or some other low figure. If your tow costs $800, then you have $500 out of pocket.
Or some insurance policies have a mileage limit. They will only covered a set number of miles. If the tow is more miles than what they allow, you pay beyond what they cover.
When an insurance company covers boat towing, they usually have limits of some kind. The terms are not as liberal as the tow coverage on your car.
The tow terms on your car aren't all that liberal either. Just auto towing is less expensive. Tow coverage on auto insurance is accident dependent generally. Tow coverage on memberships like AAA or your manufacturer's plan often have limits that consumers are shocked by. Most commonly they will not tow you where you want to be towed.
The model for the boat tow memberships was AAA and other auto programs. AAA Classic is up to 5 miles. Not much help in rural areas. Lock and Key is limited to $50, which is well under the cost.