Re: littlecofiegirl's comment — actually, the internet was never like this.
"YouTube used to be free." Youtube used to be funded by venture capitalists. It operated at a loss for many years, until it grew a dedicated enough customer base to start stage 2 of the enshittification process.
It's the same business model as Amazon or Uber. Venture capitalists pour money into a business, allowing it to operate at a loss and undersell its competition until all the competition dies out and it becomes a monopoly. Once that happens, the business can hike up prices as high as it wants, secure in the knowledge that customers have nowhere else to go.
These websites were never free. They were always accruing debt, with the intention of eventually coercing the public into paying off that debt a hundredfold.
AO3 is not a relic of the old internet. It is a new kind of website created specifically in reaction to the enshittification of the corporate internet, by a community of people who believed that creative works deserved to flourish on the internet, on a platform that was not subject to the whims of corporate oversight, so much so that they were willing to donate money and labor to create such a platform.
If you want to compare AO3 to something, compare it to a website like Bluesky, which was created in reaction to the enshittification of Twitter X.
Do not glorify "the good old days" that never existed. You don't make the internet or the world better by going back to the way things were. You do it by building something new.