Is it the case that "countless websites have none"? Some websites, especially small ones operated outside of the EU, simply don't care about their obligations under European law. But in my experience it's extremely rare for European websites not to feature a cookie banner. It's not like it's just corporations: the official websites of the European Commission (https://commission.europa.eu/), the presidency of France (https://www.elysee.fr/), the chancellorship of Germany (https://www.bundeskanzler.de/bk-de/), etc. all have one.