I dont think the question is whether fees will be more, the question is whether fees will be enough

rijndael

bitcoin

Tail Emissions Are A Terrible Idea

josh

> altcoins such as BCH manage to stay operational despite much lower miner revenue.

I used the altcoin example to show how the miners adapt to the environment, no need of protocol change to maintain security.

I believe the BCH example is bad as is a minority hash chain (SHA256). making it more insecure of what bitcoin will be in the future when we do not have the subsidy. I used this example to make a point of how the miners will behave. 
In the future, Miners will use the best technology increasing their efficiency and increase the hashrate even more of what we have today.

> I doubt one would risk settling a $1B transaction on Bitcoin if the block reward amounted to $1k.

Today (09-06-2023) the last block reward was 8600$

I don't understand why you think is going to be less in the future.

https://imgprxy.stacker.news/6YZXvuc3sG3tlvnUsRWXwZfBTqyn7XMhqcWzrqtPfYs/rs:fit:600:500:0/g:no/aHR0cHM6Ly9pLmltZ3VyLmNvbS9RUDFtTzZsLnBuZw