Measuring the new system by the old is folly. Liquidity only affects the day to day volatility but has no bearing on the overall long term growth which is powered by the mining network and the conversion of energy into Bitcoin at constantly adjusting rates. Bitcoin is literally a new paradigm for humanity. 1 Bitcoin today will eventually be the equivalent of Trillions of dollars of spending power in the future, at that time we will have updated the network to allow greater divisibility so it's still usable at such extreme valuations. This will happen as humanity continually grows it's excess energy production and gives it to Bitcoin through mining, that value exchange of ever more energy for ever fewer Bitcoin means the newly created Bitcoin buoys the value of all existing Bitcoin held in reserves.

In essence, Bitcoin creates it's own liquidity.