It's definitely not a perfectly competitive market but this trope about GAFAM being monopolies is tiring. A monopoly can stagnate development on their product, raise prices and there's nothing customers can do because they have literally no other option. That is why monopolies are bad.

If Google were to try and charge users for search, everyone would immediately switch to bing which keeps them in check from raising prices like they would if they were the only provider of search. They are in no way a monopoly.