Bitcoin supports only 600k tx/day? Proof it! I am convinced, you will quickly find the error in your very bold message!
Looking at the FUD already spreaded, I start to think that next level of FUD will be banking hubs..
Transaction throughput of legacy transaction is limited at roughly 7 transactions per seconds ie. 600,000 transactions per day, so that statement is true.
https://en.wikipedia.org/wiki/Bitcoin_scalability_problemOr used to be, as a full switch to SegWit transactions doubles on-chain transaction throughput to 1,200,000 transactions per day which is still barely a drop in the bucket.
So yeah, on-chain scaling is hardly viable. Which no one except big blockers is arguing against. Which is why LN has been implemented in the first place.
Bitcoin transactions have been declining big time. We're now at 187k daily transactions while there where 500k transactions not too long ago and the bitcoin fee was $65.
This statement is merely based on the outlier that was December. It's like saying "Bitcoin price has declined big time" which, while true, focuses on short term trends and ignores the big picture.
Mind you, even 500k transaction per day is pretty much nothing world wide, VISA processes 150 million per day for example. Now imagine that bitcoin ever becomes popular. You probably can't use LN for payments over $100 dollar or it will become difficult already to find a route, so you're doomed to on-chain payment (or open a channel and also pay the on-chain fee).
Ignoring that we're yet to find out where the viable transaction limit of LN really lies, it's kinda funny that you should mention both VISA and payments over USD 100,-.
It just so happens that at least a couple of years ago the average transaction size of VISA was below USD 100,-
https://www.statista.com/statistics/279308/average-credit-card-transaction-value-worldwide/So what you're really saying is that LN will be capable of handling average VISA transactions
