I don't think lightning is a a cure-all though it is an improvement. It allows for almost instant transactions but there are still a few caveats. I still don't think it would be sufficient to replace the financial apparatus we have today. Plus there's the fact that it's potentially much more dangerous to have all your money locked up in bitcoin, particularly if you aren't technically savvy enough to keep track of your keys, keep them safe and backed up, etc. I'm not saying it won't get there, but I don't see it happening in the near future. I suppose banks could take care off all that for you somehow... There's going to be a huge resistance to a completely cashless society though, at least in some places.