I highly doubt that will happen this decade. Except for crypto enthusiasts, the world still revolves around fiat. As long as the seller can't use Bitcoin LN to pay his suppliers, there's not really a point in keeping it.
I don't know, but I feel that if more countries behave similar to El Salvador, we may see the adoption growing faster than the internet's. The 90's was the decade when it started, but it became popular and
someone could say globally adopted 10 years later. History repeats itself with Bitcoin, but this time it'll change the way people transact value. I like thinking it that way.
LN will not get rid of payment processors. as the whole investment is to offer these payment processors a nice new niche of customers to manage.
That is also a possibility. I recently read that
Texas state clarified that banks can custody bitcoins. Sure, the centralized services might find their chance to enter this new system updated. And you shouldn't forget that sometimes people need a third-party. We've all struggled to get rid of it, but sometimes it's important to exist.
We shouldn't devastate the system that existed before just because we've found a way to transact our value with no third parties; remember, some people
don't want to be responsible for their own wealth.
The primary risk of losing funds when using LN is if you do not properly backup signatures received by your channel counterparty after every step of changing the channel state, every time the channel state is updated.
But, that's not your fault, right? Your mobile for example could
go caput anytime and that may result to loss of money. Same thing could happen in Bitcoin if there weren't things like seed phrases and everything was saved into your hard drive.