You don't see cars on google earth either, unless there's a glitch.
Large cattle herds get blurred in a weird way that prevents counting the number of animals. I ran across this when looking at imagery [1] of the recent quarter-billion-dollar (yes, with a "b") ghost cattle fraud in Grant County, WA [2]. That's right, I said ghost cattle.
I think it's only safe to assume something will definitely be left in satellite imagery if it's in the same spot 100% of the time.
[1] https://goo.gl/maps/kBPzNE9d5Qhq5h4G7
[2] https://www.beefcentral.com/lotfeeding/us-cattle-feeder-plea...
https://www.aaroads.com/forum/index.php?topic=18188.0
...which seems to check out. Cars disappear from roads (but not parking lots) only when I turn on 3D mode ("Globe view"). In normal mode, I see all the cars on freeways around Marin. Plus there are boats showing... just not 100.
I tried to find some pictures of these boats or more information. Found something here: https://pacificsun.com/tensions-rising-on-richardson-bay-as-...
More pictures (google image search for "sausalito anchor outs"):
https://www.google.com/search?q=sausalito%20anchor%20outs%20...*
The other perspective, from Latitude 38 (the local "zine" for sailors on the bay):
https://www.latitude38.com/lectronic/another-close-call-on-r...