I can pitch in a little.
I was lurking long before the Discourse move and then I finally joined in 2024 I think it was.
I don’t use the Internet heaps, I have no social media, E4 seemed like a place that was mature and enthusiastic about Pokémon for what it was, and not money, not exuberance, and also that everyone at all levels of enjoyment was welcome.
I was excited to join and enjoyed participating, even the 2020 boom and the way it was discussed and handled seemed mature and nuanced and everybody had their place.
Lately, I feel like certain voices and opinions are drowned out.
I feel also like there is a notable divide between those who are making bank and those who aren’t. I personally have no horse in this race but I’ve spoken to many who are feeling ostracised for being dissatisfied that things are so unachievable and that they should “make do” (to paraphrase.)
I feel like tensions are higher than usual and whilst this was also something I saw in 2020, it feels worse this time. And maybe just a greater reflection of the state of the world, but it feels like people are more agitated.
The narrative has shifted and as the site naturally evolves to bring in a new crowd (as it should, I certainly don’t wish stagnation for it), I’m just gradually becoming more and more detached from the zeitgeist that I see now.
My personal circumstances also contribute to the distance I feel from the hobby and by extension, E4, but as others have said, there are also so many positive people here, interactions, knowledge and truly joyful collection posts that I haven’t outright left yet… but I have considered asking for a delete more than once. 
All of the above is why I post less now and why I interact less, but for the most part everyone here is lovely and it’s still my favourite place to be on the Internet.