Towards the first point of having a limit thanks to having to sell sex appeal, while i do agree that that is the case with most categories ( shocker ) when looking at the music category it doesn't... Hell, depending on the asmr, i would even say it is negatively influencing the view count since what they now classify as traditional asmr ( no earlicking or similar things ) has them looking classy, presentable, and just overall good looking without sex appeal since they are trying to present themselves differently, more like someone yo could be friends with instead of the one you want to have sex with. With earlicking asmr, that is 100% the case that sex sells yeah, the moment that they do something like that, they have to go for the sex appeal in order to stay relevant. As for the music category, most are dressed pretty well as well. DJ's are usually just dressed like they would at a gig, but go to a good singer or guitarist on twitch and they usually wear normal clothing like a nice comfy hoody, sweater, actual pants and still get a good consistent growth both in viewership and subscribers.
As for the earlicking asmr, yeah, there is no denying that you have to sell a lot of sex appeal in order to get your viewership with that and will hit a ceiling soon enough because you can only get so far when banking on that. A bit suprised they are still doing that much earlicking on twitch since they did say in several of those blog posts that twitch would no longer monetize those with add revenue for the same reason as pool streams would no longer be promoted and paid add revenue. Point 3 and 4 might actually be the thing that is hurting her income the most when i think about it. Sure, she had a bit of growth in the hot tub, but going with the public available stats, the hot tubs were actually hurting view count while the asmr got her to an average of 5K, with the highest number i could was 8K of viewers at the start so either she ignoring that people don't like to be mocked and talked down to or she is trying to cater to the people that like to be stepped on. Both are not a good thing...
As for the second point of her only doing asmr, she used to do nice asmr for her youtube with natural elements like water but the moment earlicking was added, she ditched the good ones as they were not making enough views compared to the earlicking ones which was a dumb decision but eh. Her choice to ruin long term income for short term profit i guess. As for your other points, i fully agree there yeah
