Can confirm. Bitcoin can scale but is being artificially limited in favor of off chain solutions.
Seem like you don't see the x^n argument. It should be obvious. Satoshi/Hal Finney were well aware of this, see the link. This has nothing to do with SPV. Producing blocks is what's important.
I searched the link. Satoshi did not post in that thread and there is no mention of "x^n"
Maybe you should present the argument, since it wasn't presented where you said I'd find it.
https://bitcoin.org/bitcoin.pdf
Moreover it a red herring to assert that Bitcoin has to scale to support every single financial transaction in the world just like it would be a red herring to attack the architecture of the Internet because it cannot scale today to include every form of communication we perform today.
Red herring/ strawman / Nirvana arguments are the defense for the entire small block position. Bitcoin, like every other information technology, does not need to meet every need today. It simply needs
1. Sufficient free capacity to encourage growth, and
2. Continuous improvement