The challenge is driving to your boat and parking.
i moved here in 1979 from Hawaii where I grew up. I moved here in spite of Seattle, not because of it. I really moved here because it's next to British Columbia.
In my opinion Seattle is one of the most screwed up cities I've ever experienced on the planet. It can't do anything right anymore, from digging a short highway tunnel to applying common sense to traffic management. The mayor and the city council lurch from one bad decision to another, most of them anti-business to the point where Bellevue across Lake Washington is booming while Seattle struggles.
For boaters there is a great solution to the traffic, poor and expensive parking, and ridiculously high moorage costs in Seattle. Keep your boat somewhere else.
We keep our boat in Bellingham up near the BC border. It's an eight knot boat, but even at that speed we can weekend in the San Juan Islands no problem. If we had the same boat in Seattle, we'd get to the islands once or twice a year on vacation.
We can drive to our boat from our home in two hours or less. If we kept our boat in Seattle the heavy traffic and idiotic road designs means it takes the better part of an hour or longer just to get into the city and to the marinas in or near the city. So even though our boat is 100 miles from our house, in reality it's not much of a time penalty over keeping the boat in Seattle.
Bellingham is not the only choice of course. South of Bellingham Anacortes offers both city-owned and private moorage and the islands are right across the channel. South of Anacortes the quaint town of La Conner on the Swinomish waterway has a nice marina and other moorage opportunities. Blaine, north of Bellingham and right next to the BC border is another choice for keeping a boat.
As a bonus, moorage up north is considerably less than in Seattle. Parking is plentiful and free. Traffic is non existant and, depending on one's schedule, the drive north can be speedy by freeway or scenic on the side roads in the Skagit delta and along the shore to Bellingham.
The photo is the view from our slip. The islands are the San Juans.