I do sometimes muse about this. I look at some of the book prices I see and raise an eyebrow, but I'll admit to being completely ignorant of the economics of publishing. I don't think anyone's really stringently made the case for where book prices need to be to make for a healthy market - and where they need to be for an author to make a living off of X books sold.
I have to admit that right now I'm a contributor to the problem. Part of that's because I know I've got enough moves ahead of me that buying more physical books is only causing me a problem - and once I'm buying kindle only, I need to be actively pro-Help This Author before it makes sense for me to pay more than 99p as there's more good stuff at that price point than I can ever read. Tbh, I could probably go an entire year without needing to buy books at all between ARCs, free indie published books and what I've already brought, and if I was more omnivorous and a more prolific/more shameless book blogger, multiple years. And there's simply no major publishing house authors active where I like their work that much.
But part of it is I like really cheap books and it's not my job to figure out sustainability (yet...). And tbh, most of my favourite media producers from where I was aware of it being a thing fitted in part time around their other jobs (mainly metal musicians) so I always kind of expected for it to be a second job unless I lucked out.
Someone needs to set out the economics though.