For many of the mentioned reasons we keep our boat in the water all year. We put 17 nights and 120+ hours on it in the last year and thats not bad for two full time workers with a three year old. If we had it on a trailer, we would have used it less than half that much I am sure. I have calculated costs and thought long and hard about both arguments and I see how different folks in different places would have different results.
For Us.....
We only pay 192 per month at Port Orchard Marina for a covered 28' slip and that includes taxs,fees, and some power use. Add that to about 100 bucks every three months for in-water hull cleaning and zinc service plus a nice coating of Multi-season non-ablative paint as seldom as every 3-4 years (with that cleaning and regular use) and the costs are still less than 300 dollars per month including setting aside nearly 1000 bucks per year for bottom paint.
Now we don't have a trailer for our 25 and we don't want one although we do have an entire lower section of our property with it's own driveway with power hookup that we have used for trailer parking so storage is not the issue.
I have no emotional or functional need/excuse to own a large truck capable of safely towing our boat. We have owned tow vehicles and towed travel trailers for the last few years and I actually don't mind towing things around but how much would I spend to purchase,insure, and maintain a vehicle capable of towing our loaded boat? I know it would far exceed 300 per month for us and simply add expense and complication to our boating life. I could drop a car and drive it around all the time but I generally drive an honest 40,000 miles per year and that's just too much gas.
Do we miss the trips to inland water bodies? If we were moored somewhere more restrictive than the gateway to the inside passage, maybe, but we travel alot and also keep kayaks and a little motor boat handy to visit them. Honestly, until there are whales, tides, and general mystery in those lakes, they won't fulfill our boating wants.
I know this applies easier to me in the northwest than some of you in harsher climates but I still think the below statement is a good measure.
If I ever find myself "winterizing" or storing something, I re-evaluate why I have it and if I am using it enough to justify its existence in my life. And yes, I have sold many fun toys in my short life.
Our C-dory will be sold before it will ever be winterized by us. It has heat, an enclosed cabin, batteries galore, and shore power for that "off season". Winters are quiet out here and we like quiet on the water as well as off.
Thats our take as new boaters but old recreationalists.