[markburns]

There's not really a problematic upper bound for global transaction volume on transactions per second with the lightning network. There are other problems in terms of adoption and infrastructure etc, but the actual potential for humankind to have a single currency global low-barrier payment system is there. But this is more like the early days of the internet. The internet seemed pointless to most people even as late as the 90's.

A future global system could have settlement on the blockchain. Like the current system does at far less regular intervals than the processing power of non-settled transactions.

[TimJRobinson]

> There's not really a problematic upper bound for global transaction volume on transactions per second with the lightning network

There unfortunately is, to open a channel you have to make a Bitcoin transaction, and you can't use lightning without opening a channel. Bitcoin processes a max of ~220M transactions per year so to onboard the world onto lightning with only one channel each would take a few decades.

A real layer 2 could solve it, or having some trustless way to use BTC on other chains

[markburns]

It's possible I'm too optimistic on this point. I feel I have a good grasp of how bitcoin works, but when it gets to layer 2 it gets fuzzier. The initial discussions sounded really promising, as they seemed to mirror HTTP on top of TCP/IP. And we all know how much of a slow burning revolution that turned out to be.

But http seems simpler than what I've read about lightning more recently.

Total wild speculation follows:

As for the channels problem, it feels to me like you have something like ISPs or AOL being the thing that's needed to kickstart it. And perhaps the ISPs or AOL in this world are the employers and lightning banks. So yes you need bitcoin to open it, but with an employer you have the potential to have an entity with bitcoin resources and with a reason to send bitcoin to an individual.

Perhaps HD wallets with lightning kickstarter funds apportioned to new employees. This feels similar to the needing a bank account or national insurance number in the UK (social security number? in the US) to start getting paid, or similar to needing an internet connection. Yes you could choose to get paid in bitcoin and have the fees come out of your wage, and this would be similar to getting paid in physical cash today. Or you could get over the slight roadbump to get you onto the lightning network.

What would a real layer 2 look like in your opinion?

[TimJRobinson]

A real layer 2 would look more like something built on Ethereum (can see all its L2s at https://l2beat.com).

Essentially it's a separate network that every few minutes takes every transaction and compresses it into a data blob that it saves on Ethereum along with a proof that the computation was done correctly. The Ethereum L1 nodes then only need to verify the proof instead of re-executing all transactions that happened on the L2.

With this design users can go straight from an exchange like Coinbase onto the L2 and never need to use Ethereum, and fees are 10x cheaper because of the data compression. Fees will soon be 100x cheaper as Ethereum is adding extra space just for these L2 data blobs that is much cheaper than normal Ethereum data space.

Unfortunately it can't be done on Bitcoin right now because Bitcoin nodes don't have Turing complete scripting and so can't verify the proof that an L2 posts to Bitcoin.