It is alleged they stole 119754 BTC, which in 2016 was < $1000USD. Which would have been < $100,000,000. Today, it is worth 5bln. (not that 100mm is nothing.... but it is a lot less).
Could you imagine stealing something that most people thought was a toy. Suddenly it became so valuable that the government could justify who-knows-how-much resources to catch you?