Because they have more money.

I've had to deploy a combination of Cloudflare's bot protection and anubis on over 200 domains across 8 different hosting environments in the last 2 months. I have small business clients that couldn't access their sales and support platforms because their websites that normally see tens of thousands of unique sessions per day are suddenly seeing over a million in an hour.

Anthropic and OpenAI were responsible for over 70% of that traffic.