The more you use Lightning and the more channels you have open, the greater the potential savings on fees. Each time you can avoid making on-chain transactions, that's one less mining fee to pay. Financial incentive will be the driving force for having multiple channels open. Incentive itself will provide the liquidity.
But each time you open a channel you pay the on-chain fee, which would be very steep if bitcoin would ever become popular. So I just don't see people opening tons of channels and put a lot of money in each and every channel. That just makes no sense.
Lightning opens up two new choices for how to transact. Opening a new channel, or routing through one of your existing open channels. If this scenario of no sufficiently funded channels occurs, you might not be able to route through an existing channel, true enough. So you open a new channel. Or you send a regular on-chain transaction. Not exactly rocket science. Plus, that's still more options overall than you previously had, so if one of the two new choices isn't available, that doesn't constitute a failure. I'd rather not repeat myself, but, "the only "problem" it creates is that you now have a choice which you didn't have before. There will be times where you might use Lightning because it's cheaper, more convenient, or both. There will be other times where it won't be those things and you can transact as you always have done". How can something that gives you more freedom and choice than you previously had possibly be a bad thing? I can see how it might look bad if you haven't taken the time to comprehend how it works, but that means the failure is on your part and not Lightning's.
The thing is, you compare it to the on-chain form of bitcoin. But that makes no sense, that's a failure already. You need to compare it to VISA for example.