The processes are all very subtle and underground. As best as I can (tongue in cheek) reverse engineer it, the process was:
Professor P publishes in journal J.
He recommends that his students publish there too.
Index X indexes J and thus all of P's work and his students work too.
Professor P is casually asked by Admin A, how research productivity can be measured. He (half jokingly) recommends Index X.
Bigwig B in admin steals the idea from A, and mandates that all promotions at the university will depend on X.
All staff in other faculties learn only via the grapevine that X is now being used (even though it does not cover the premier journal in their fields).
At accreditation time, the representatives from universities in neighbouring countries ask how many publications the university has in X.
I leave it to the astute reader to work out where opportunities for corruption and cronyism can creep in.
In general, Scholar does not index predatory journals, so the predatory journals now go and make up their own imaginary indexes!
You are free to publish anywhere you want. The truth of the matter is that all the good journals are indexed somewhere. Which one your paper is indexed in will depend on the index's coverage. No-one is forcing you to be indexed by any particular indexer. However, my Gut feeling is that Google will Get you!
What you are being forced to do is to consult the indexes when surveying the literature.
The point I am making is that institutions now want o be ranked and that means that, if you want to be promoted at most institutions, you must publish in a scopus indexed journal. The collusion is indirect!
They are competitors. Impact factor is calculated by Thomson Reuters (web of science and ISI under the umbrella of clarivate analytics). These are are not free. Google scholar has developed an h5-index (similar to impact factor) which is freely accessible. Disadvantage of google scholar is that it indexes even predatory journals, hence your h-index in google scholar is likely to be higher than than in web of science or scopus. By and large, i agree with Farid.
The processes are all very subtle and underground. As best as I can (tongue in cheek) reverse engineer it, the process was:
Professor P publishes in journal J.
He recommends that his students publish there too.
Index X indexes J and thus all of P's work and his students work too.
Professor P is casually asked by Admin A, how research productivity can be measured. He (half jokingly) recommends Index X.
Bigwig B in admin steals the idea from A, and mandates that all promotions at the university will depend on X.
All staff in other faculties learn only via the grapevine that X is now being used (even though it does not cover the premier journal in their fields).
At accreditation time, the representatives from universities in neighbouring countries ask how many publications the university has in X.
I leave it to the astute reader to work out where opportunities for corruption and cronyism can creep in.
In general, Scholar does not index predatory journals, so the predatory journals now go and make up their own imaginary indexes!
Web of Science, ISI, Scopus, Google Scholar, and so on, have indeed some value in organising scholarly knowledge. However, we need to search for a new ecosystem to further promote issues of quality and impact. See e.g. http://blogs.lse.ac.uk/impactofsocialsciences/2018/01/23/quantity-does-matter-as-citation-impact-increases-with-productivity/