Block size has not been changed over the last 5 years, this is what I mean by people fundamentally misunderstand the issue. That shows transaction fees increase as transactions increase with a fixed block limit, but simultaneously shows fees do not have to keep rising since we are not at the limit (when transaction volumes reach the highest levels). That break from linearity at the end might be the stress test too, but that was good proof of my point we're discussing so it's still valid.

Think of it like the oil market. If block size is increased that's like discovering another Saudi Arabia and will flood supply, directly forcing total transaction fees downward.