Transaction fees for bitcoin sent via the lightning network (which is a layer 2 solution) are in the "less than a cent" category and are settled in a few seconds. This is not fiction, this is i.e. how Trump made his for-the-cameras bitcoin payment during his campaign.

Lightning isn't even a good solution for most diehard bitcoin users. It's a failed project.

It would take 27 years to onboard every internet user to the lightning network unless you start adding level 3 aggregators and then at that point you lose all the benefit of it being on chain at all.

It would take almost 2 years just to onboard every American assuming during that time there were zero other bitcoin transactions. Then you need to add the fees for the on and off ramps to the individual transaction fees to get the real cost per transaction noting that these would go up quite a bit as the competition between lightning and non-lightning uses of the transaction space would drive prices higher.