But reality is, without incentives, Bitcoiner's can't be expected to take/accept the opportunity cost to lock their capital, Bitcoins, in Lightning channels.
there is an incentive. It's more long-term, but the reward is bigger.
The people that provide liquidity to those who need it most will be rewarded. Those who do not will need to hope they get lucky, and that a dissimilarly self-less person provides to them some incoming liquidity.
I admire the optimism, but I don't know how an ordinary user will be expected to be in it long term, unless he/she is incentivized from the level of specialization in maintaining a Lightning node. But I see a debate for altruism to boot-strap the network.