Some simple math.
Assume we have 30 mil bitcoin users.
Every user should open a LN channel and close LN channel.
Bitcoin can handle 300 000 transactions per day.
30 mil users should wait for 100 days so every one can open a channel, and 100 days to close a channel if there is no other transactions besides LN settlements in bitcoin network.
300 mil users should wait 1000 days, so every user can have openned LN channel.
Bitcoin can't even adopt Lightning Network without big blocks. LN official release will lead just to another huge fee spike, and since LN channels should be restarted regularly bitcoin network can be clogged by LN settlements.