Sure- just like any major entity can influence any variable.

Governments, however, are likely not doing this because they stand to gain from cryptocurrency. Malta is going to see double digits GDP growth in 2018, Venezuela will be able to circumvent trade sanctions, France will lead major tech innovations. All of these advancements are happening through blockchain acceptance. Governments stand to be much bigger winners than fostering crypto businesses and activities than to try to squander the industry as a whole.