We can imagine 100 different websites each with different non-personalized algorithms - another algorithm decides which one is best for you and directs you to that site. That's effectively a personalized algorithm with extra steps.
Yeah but then each of those websites would only have 1 audience, which would be economically ruinous. Even HN has >1M daily view which is quite a lot of eyes to cater.
I guess there can be a sweet spot in a certain amount of MAU. And this is why I prefer medium-sized subreddit.
That's where we are. HN is one of those sites.