Depends entirely on the field. None of the (psych/behavior) journals I'm familiar with ask for things besides DOCX.

I think it all comes around to how the funds are distributed.

Researcher gets grants from the federal government to enable their work. They do the work, write the paper, get it accepted to a conference. They're required to attend and present to get it published. So they have an excuse to buy flights, hotels, expense food all on government dime. And the conference is put on, in part, by other researchers, who aren't going to use their own funds to put on the event. So they charge people to attend, and those who want to get published have the largest incentive to attend, so they can be charged the most.

I only did 2 years of graduate research and attended a handful of conferences (unpublished unfortunately)... I could have this wrong, but I'm pretty sure this is the way, at least in the computer science field.

Oh absolutely. It's a huge issue, especially in humanities and social sciences, where the barrier of entry makes it so that almost all published research is conducted by certain populations on themselves. Some people call it "WEIRD" populations, meaning western, educated, industrialized, rich, and democratic (though that "weird" terminology is a bit stinky... I'm looking at the "E" and "D"). Interestingly, China has now overtaken the US in publishing the most highly cited research of any country, though I think their advances are mostly in natural sciences and engineering.

There are also issues with how we qualify good quality or *academic * research. Again, this is especially the case in social sciences and humanities where the standards have been set by colonial researchers who had the means to run expensive studies on large samples. As a result, a lot of research methodologies and ways of knowing that don't align with the western colonial standards (e.g., qualitative research, narrative analysis) get discounted or written off entirely