"The reason why everything is ruined by advertising is because nearly everybody expects content to be free to the end user on the internet. The money has to come from somewhere, so advertising it is."
The internet was doing just fine before corporations and advertisers swarmed on to it in the first great internet gold rush.
If you define "doing fine" as only available to a limited few and barely sratching the surface of what was possible with the technology then sure. But to scale it to a broader audience and to empower more business models than just hobbyist site and university faculty pages you needed a way to fund it.
I was there before the gold rush. If you had a page on the internet and it got at all popular half the people who visited would see either a notice from the hosting company that the page was no longer available because some limit had been reached or you would get some outrageous bill from your ISP. Only a limited few people could afford to visit the internet let alone publish on it. It had a certain exclusivity that came with certain benefits. But I'm not sure that staying exclusive was either a good idea or useful to society at large.
Advertising in the early days helped the internet provide real value to more people than ever before. Like many good things though taken to extremes it has particular failure modes that we are seeing now. That doesn't mean introducing advertising was the problem necessarily. It does mean that controlling the failure modes of advertising is probably necessary for a well functioning society.
Yeah, but it was also very much a thing for academics to play around with. Commercialization democratized the internet and let normal people access it. That usually makes it more crowded and degrades peak quality.
And, to be honest, I much prefer today's internet and technology with all the flaws to what was there in the 90ies. Commercialization and turning it into a mass market is what drove innovation.
The internet was doing just fine before corporations and advertisers swarmed on to it in the first great internet gold rush.