let me counter your anecdote with mine: I saw something somebody else picked, and it was complete trash. In fact, this is trivially the case every time I see anything awful that has at least one positive review. Judging by, say, RT page for the last jedi, this is a common experience.
It's all about the signal to noise ratio. It is more likely that you'll enjoy a work that was enjoyed by people similar to you. It is also possible that you'll enjoy a work recommended solely by some random pseudonym on the internet, but less likely.
everybody's always in a bubble, since there is a finite number of hours in the day and far more media than anyone can consume. The best we could hope for is to personalize the bubble while minimizing the influence of outside interests with divergent goals - e.g. advertisers and spammers.
I imagine the change of preferences can be tracked over time by periodically rating new works I consume and having critics fall in and out of the personal overton window.
Is there a service like this: rate a bunch of media, then filter for critics that largely share your preferences, then subscribe to recommendations from just those critics? If there isn't, there totally should be.