100% Untrue. I use many extensions in Safari just like I use to in Chrome, my needs for customization are the same regardless the browser I use, but like many choose Safari for his performance, privacy ui, among other benefits. Find it very frustrating that many of the big products don't have Safari extensions. Often when I email there tech support they give a reason why, and then I try to explain there are referring to how extensions worked before, rather than how Safari extensions work now. So imagine a lot of companies don't know about the changes, or think they don't need to because they don't have enough people asking for them, but people probably did ask for them but were told it was not possible before, so they stopped asking.
I get why it may seem that way when we're on HN and there's selection bias going on. But if you look at all major browser the Safari users are going to be the lowest % extension use. That's what Apple is. An ecosystem where users don't configure anything. You can go out of your way and do it but that type of user is not who they design for.
I remember when people said ad blockers we’re going to be broken. And I didn’t notice because the ad blocker I was using before worked fine and continues to work fine after whatever they did. (1Blocker)