Based on what you wrote, it doesn't look like you used reddit for too long. Most of the more interesting things on reddit are very niche (hobbyists), very personal (old askreddit, helpful supportive communities for minorities, big comment threads about global events, etc.), or very regional specific (food, culture, belief, etc.) There are quite a lot of people still use small subs on reddit exactly for those reasons, finding very technical or obscure knowledge is only possible thanks for small communities. That is what many wish to replicate here.
I do not get what you even mean by saying niche subs will survive as they did before. No, there are a lot of sub drama and not all sub survive drama, and this time reddit itself is trying strip contents and agency out of the users and mods. What do you even mean saying it won't effect small subs?
If you just doom scroll lookking at meme pics and comments you aren't really experiencing much other than dopamine content. Just because you do not engage in smaller communities doesn't mean that these changes aren't affecting those people.