Even more: Adam once claimed that the LN would achieve 10'000 transactions for every blockchain transaction. Leaving aside what that would mean for the coin lock-in periods of the channels, the rate of 1:10'000 is so close to 0:10'000 that no one would notice if the LN just dropped bitcoin altogether, and from then on just shuffled its "cryptochecks" around indefinitely, without ever settling them.
Of course, LN users would never accept that. It would be like that time when the US government decided that dollars would no longer be convertible to gold or silver. We all remember the revolts in the streets, and the huge bonfires where enraged dollar holders burned their then-worthless bills. Right?
Conversely 1:10000 is so close to 0:10000 that you might as well just leave it on the Bitcoin blockchain. The benefit of not doing so would be negligible.
BTW, I'm pretty sure the LN people have stated that block size increases of some sort would be needed. I don't know where Blockstream stands on this. Maybe they want people to anchor their channels on their Improved Bitcoin Sidealtchain instead of Bitcoin.