Because people need something to point to to try and act as if this isn't a dead industry so they can keep you in it spending your money
SEO as far as ranking a niche site on Google is concerned is dead, but so many people have built their livelihoods on selling the dream and some are shady and act as if all you have to do is spend money on links and problem solved
But in reality, how many links do you think you need to buy to catch up to the behemoth sites that take up 90% of Googles page 1 like Yelp, TripAdvisor, Reddit, Quora, ESPN, and whatever legacy brands Google still chooses to rank?
They have millions if not billions of backlinks, are you willing to spend $10k to get .1% of the backlinks they have? If you don't think that is going to make a difference then are you going to spend 100k or 1 million?
At this point Google is so clearly broken and only a fool would continue to pour good money down the drain chasing something that is most likely never coming back