Predicting timelines is always a guessing game. But I'm actually of the opinion that in the near term, liquidity on the network is not a bottleneck for Lightning. We can still scale to way more payment throughput and success rate with exactly the same amount of liquidity we have right now.

Liquidity is a good that will be present as soon as sufficient demand is visible. When people want to use Lightning, the liquidity will be there. When large exchanges adopt Lightning or new merchants come onboard, they will bring the liquidity they need themselves, or attract it by exerting demand.

I'm not convinced that Lightning will be a great place for "yield" in the near future either. It may be a good place for "risk-free rates", but not for earning substantial yield, compared to shitcoin schemes, bonds, or the stock market.