Governments are collecting taxes on bitcoin and income from the bitcoin. In countries which are recognizing bitcoin or crypto currency as property will attract the property tax, whereas in countries where bitcoin is recognized as the accumulated wealth will be taxed under the wealth tax. This wealth tax is applied to the gold, silver, other precious metal and stones like diamond, ruby, perls etc etc. 21M bitcoins is not going to kill the bitcoin, in fact it is that number which has kept bitcoin users loyal to it. Because of limit on crypto coins, there is trust among the users that if tomorrow bitcoin touches a million per coin then devels wont take advantage of it by increasing more coin limit. This scarcity is the one of reason for price rise and loyalty.