Marketing people actually know & plan for this. Check out this blog post about "The Lifecycle of Lead Generation Channels" [0].

It basically says, that any given channel starts out small and high-quality, so engaging is easy and credible. As it grows marketers have to be smarter and larger to stand out. Read it as a consumer, and they're basically talking about a scorched-earth loudness war for your attention.

[0] https://medium.com/point-nine-news/the-lifecycle-of-lead-gen...