It's true that nobody knows for certain what will happen. I am skeptical of the idea that bitcoin in particular will be able to scrounge up enough fees on "L1" to keep the network secure, especially given its small throughput.
As the author mentions, the "L2" scaling solutions like LN still require security on "L1". However, to the extent that "L2" is scalable, it will not increase "L1" fees.
I won’t argue with you on this point. A better way to phrase it might be to say “POW has many features or implications for Bitcoin…”
> There are PoW cryptocurrencies like Monero, Litecoin, and many others that have community-driven development and institute a less dangerous emission schedule than Bitcoin.
Disagree that it is dangerous. We don’t have enough information about the future to determine that. It is just as likely that fee markets will be enough, thus implementing some kind of “perpetual emission” would only damage the value of the network.
Nobody will know the answer until it happens.