The internet was doing just fine before corporations and advertisers swarmed on to it in the first great internet gold rush.
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.
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.