While true that it is becoming harder to shop Amazon, like it is becoming harder to search on Google, because everything is an ad, and while true they are awful in many respects, they have nailed one thing: convenience.
Shopping everywhere else has more friction. In the best cases, it is 1% more. In the worst cases, I give up on the checkout process and submit to the Borg and just buy it on Amazon, sometimes for more money.
Also, Amazon gives the illusion of security. Somehow, it never seems to figure in major headlines about data breaches and compromised credit cards and so forth. And yet...
https://firewalltimes.com/amazon-data-breach-timeline/