> Indeed, any powerful entity can buy anything online: clicks, bots, comments, views, accounts, literally anything they want to say can reach millions of people. This would be ameliorated by ethical and moral information platforms, which we seem to not use and not build for profit reasons.
There's still a marketplace of ideas. Powerful entities will be competing with other powerful entities for bandwidth and attention. The people themselves will decide which messages they wish to pass on and spread and which they don't. If it was as simple as you say, the person with the most money would always win. While that does happen, we can see the from the results of the 2016 election that it doesn't always work that way. Clinton spent far more on traditional advertising and guerrilla internet tactics (c.f. Correct The Record) and didn't win because her message didn't resonate with enough people.
Long story short: free will still drives the internet and outcomes. Advertising isn't very effective and when it is, advertisers will be competing against each other for the limited access to that scarce effectiveness.