even with LN or sidechains, funding and settlement = on-chain transactions. we'll eventually run into the same congestion and high fees with or without a concerted effort to spam the network.
are you opposed to any future block size increase? i've got mixed feelings myself knowing how difficult it might be politically. i'm curious how others see the issue---assuming the technological (network latency/bandwidth) bottlenecks are overcome.
It's not that im opposed or not, is that I really doubt it can be done, at least done smoothly... every hardfork is going to be a bit of a clusterfuck situation unless it's an undeniable necessity. Some may argue that it's never really needed because as long as there's people willing to pay to transact, then things go on as usual. Others may argue this damages some of the economical incentives but im not so sure about that.
In any case, in order to fill the current block space worth of LN transactions, the usage of LN would be massive.
I think blocksize will eventually be raised, however it will probably happen when the situation requires a hardfork for other things as well... we'll see.