More and more people who don't trust the global banking system anymore.
More and more people who don't want to pay tax on everything.
More and more people who want to shop online without being traced.

BTC's growing, and so is the number of people using it.

It seems correct to say that the supply side is growing faster that the demand side right now, but we know the supply's growth will be halved sometimes, so we shall remain confident in the longer term. There will be a day when demand will outgrow supply, just like it did last year.