Probably a very polarizing question.
On the one hand, having most of the users and communities on LW causes technical issues (see this post), and also gives the LW staff too much power over Lemmy as a whole.
On the other hand, with 18k MAU on LW out of 47k (https://fedidb.org/software/lemmy/), every community listed there has a much higher chance of visibility compared to an alternative hosted on another instance
History of LW controversial decisions
- when they promoted Discord as an official communication channel (https://lemmy.world/post/3478399 - since then they created a Matrix chat)
- when they blocked the piracy communities (https://lemmy.world/post/13320356 )
- when they announced they might move from Lemmy to Sublinks (some comments from LW admins were quite controversial: https://lemmy.world/post/13899357 )
- when they forced the media bias fact checker bot and discarded user feedback (https://lemmy.world/post/18775630 - to be fair, they since then removed it from !news@lemmy.world , it’s still in !politics@lemmy.world )
- when they realized centralization of communities on LW was impacting the ability of other instances to stay up to date (https://lemmy.world/post/13967373 )
- when they updated their rules following a power trip overtake of a community (https://feddit.org/post/2308651 )
Definitely, but I guess the amount of sysadmins wanting to operate a lemmy instance is limited. Add to that the CSAM and other nasty stuff that happened at the beginning, and only a few people would be okay to manage their own instance.
Also, even a topic-focused instance would suffer from the lack of population. How many interesting topic can you find for a population of 50k? That can’t be too precise, because you are talking to a very small population. Well, I guess that’s why db0 and slrpnk are doing well, piracy and solarpunk are popular among Lemmy users (as well as whatever the political stance of lemmy.ml is)