Earlier quoted context omitted.
Wikipedia is not funded by ads for example. Lots of other sites neither. So I would say, not the whole internet would go away without ads, but probably the worst parts and what remains is worth visiting.
But how many Wikipedias can there be? They got funding because they are large and have reputation behind them. If you tried starting up a new Wikipedia to compete, guess he much non-advert funding you'd get? Look at how quora tried and failed hard, and have to sell out to survive. Look at stack overflow these days?
You don't need resources if you are small and unknown. Run it at your house until you have a few thousand users, and then move to something like Hetzner (if you're one of those Swiss people with 25 Gb/s Internet, skip step 2). If I'm interpreting their grafana[0] right, Wikimedia gets ~20 edits per second and usually peaks less than ~200k requests/second across all projects, and it looks like traffic has not exceeded 7 Gb/s over the last 90 days across all data centers. Even the largest projects are not a lot from a technical perspective these days.