Well, given that some sites employ hundreds of trackers and other barely-above-malware stuff, it does make sense for these requests to take ages.

Unfortunately, many people simply click on the "accept all" button and don't care about their privacy that much.

The idea of GDPR was that consumers would be hesitant upon seeing the massive amount of third parties that use your data and demand change from the providers, turns out people don't care / providers rather let privacy-oriented customers suffer than to take a hit on their advertising profits.