Earlier quoted context omitted.
LN requires opening and closing channels, each of which have to be done as a regular Bitcoin transaction. The value proposition of LN is that repeated transactions with the same entity (or some subset of) can be done without high fees, but considering almost nobody is currently using LN that doesn't change things right now.
Channel factories will bundle channel open/closes into a single transaction significantly reducing the burden on the blockchain. LN adoption is growing very nicely (1ml.com), there are lots of wallets and users now.
If I understood the Satoshi paper right, after the block reward is exhausted the network's security depends on transaction fees being high enough to sustain a strong level of security. If Lightning brings transaction fees down, is that not a threat to the security of the network as the block reward becomes smaller?