The web had little to do with APA’s decision to adopt one space as the standard. It was desktop fonts in the mid-eighties. Two spaces emerged as a standard when fonts were monospaced - they were a readability hack. When proportional fonts started to be introduced, two spaces began to look visually odd. That oddness was especially apparent in groups of sentences like.

“It’s hard to learn how to spell. It takes practice, patience and a lot of dedication.”

^ In a proportional font the difference in width between ‘ll’ and ‘ ‘ is noticeable. In a monotypes font, two spaces after a period provide a visual cue that that space is different.

I think this is why this all lowercase style of writing pisses me off so much. Readability used to be important enough to create controversy - nobody cares anymore. But, I didn’t care enough to read the whole article so maybe I missed something.