To put things in perspective, a typical certificate is a few kilobytes. Let’s say 10KB of network traffic to process one certificate. This is just 3.5 Mbps, and we’re all “very impressed” that it’s being provided for free. A Raspberry Pi could serve this. Certificate Authorities have convinced everyone that their service is so onerously difficult to provide that they deserve billions of dollars… annually. The reality…
To be fair, I doubt bandwidth has ever been a significant cost driver for CAs
DigiCert for example is owned by private venture capitalists.
They expect as much rent-seeking as possible to get a return on their investment.