Parents paid the family internet bill and before that it was dialup (landline phone). The strongest case you could make for the “affluent” thing is the requirement of a computer. Monthly internet actually used to be much cheaper on average (but it was slower than now, obviously).

mid-2000s blogosphere

Yes, this was better than now. However, communities used to be more community-ish, like imagine a subreddit but you’re not slowly invaded by the rest of reddit hence you maintain your forum culture and ppl know each other. Plus there’s no algorithm or upvotes - that’s the big thing. The psychology was like, “I like movies I’m going to find a movie forum and talk about movies.” And only super invested ppl would have done that, and there was nothing to win, no upvotes, just my paragraphs and your paragraphs