Reasons?
Click bait, boosts consumerism, ads imply essentially a tax for everyone (remember that ads have to be paid by the consumers), CEO spam, annoying, environmental costs
Removing ads would require being willing to make micro payments to some random shady news site you found on google to read their article.
In the current payment world, that would require sharing a lot of private information in the case of PayPal or, even worse, sharing your CC number.
The Digital Euro might fix this, if it turns out to be well implemented.
Once a well implemented Digital Euro arrives, an internet without advertising would be a real possibility.
Don't we live in a capitalist world?
The economy should serve the people, not the way around.