Because Bitcoin is not a major concern for them. Just a minor concern, a niche used by smart people as inflation shield.
I do not agree with you. If you look at all BTC related charts you'll see a growing users base, growing exchanges, growing value, growing market cap, etc... It is no more a gadget for smart and geek people. It is slowly getting mainstream. Governments could soon see it as a serious problem and make the use of BTC really hard by banning exchanges, BTC ATM, ....
Bitcoin may not be banned, but yes if key countries take steps against Bitcoin, the other countries might also do the same. Mostly I believe it will be regulated, Bitcoin became very important to many peoples, we have to admit it helped in business as a new transaction option.