Ask HN: Why people pay SEO tools?

I've been in a project that they need to improve the website and keep coming with the SEO importance.

Beyond I believe advertising is broken right now, I am a developer that feels confident with tools like Lighthouse and passing the basic checks will do the trick.

But it seems there is more behind. One of the major existential doubts I have is: Why are so many companies doing paid backlink checks and stealing money to the customers?

Do exist an Open Source initiative to give some clarity to this problem and reduce unnecessary costs and break the spending flywheel for normal users/companies?