In my understanding, number of bitcoin users now is only 350,000, less than a million at least.

When it reaches 100 million, we are still in early adopter phase in global scale.

It is very important to realize that all growth has its limits, and the limit for bitcoin growth is that it replaces all other liquid wealth. That would lead the purchasing power to be in several million$ range. A more conservative scenario, that of replacing gold, would put the price at $300k/BTC.