Sorry you don't believe me.
Here's my own photo evidence from South Beach in July 2017. https://photos.app.goo.gl/JzporX8XmFFswgSu8
I didn't go in 2018, but 2016 and 2017 I was there for about a week. same empty beaches both trips.
You being there in Nov may be why you see seagulls, I never have been there in winter.
I don't have any photos handy from the 1980's to scan, but it truly is a stark difference.
I can't speak to the pacific northwest 30 years ago so I'll take your word for it that there were more birds on the coast then.